14 A Rare Fossil Record
The preservation1 of embryos2 and juveniles3 is a rate occurrence in the fossil record. The tiny, delicate skeletons are usually scattered4 by scavengers or destroyed by weathering before they can be fossilized. Ichthyosaurs had a higher chance of being preserved than did terrestrial creatures because, as marine5 animals, they tended to live in environments less subject to erosion. Still, their fossilization required a suite6 of factors: a slow rate of decay of soft tissues, little scavenging by other animals, a lack of swift currents and waves to jumble7 and carry away small bones, and fairly rapid burial. Given these factors, some areas have become a treasury8 of well-preserved ichthyosaur fossils.
The deposits at Holzmaden, Germany, present an interesting case for analysis. The ichthyosaur remains9 are found in black, bituminous marine shales11 deposited about 190 million years ago. Over the years, thousands of specimens13 of marine reptiles14, fish and invertebrates15 have been recovered from these rocks. The quality of preservation is outstanding, but what is even more impressive is the number of ichthyosaur fossils containing preserved embryos. Ichthyosaurs with embryos have been reported from 6 different levels of the shale10 in a small area around Holzmaden, suggesting that a specific site was used by large numbers of ichthyosaurs repeatedly over time. The embryos are quite advanced in their physical development; their paddles, for example, are already well formed. One specimen12 is even preserved in the birth canal. In addition, the shale contains the remains of many newborns that are between 20 and 30 inches long.
Why are there so many pregnant females and young at Holzmaden when they are so rare elsewhere? The quality of preservation is almost unmatched and quarry16 operations have been carried out carefully with an awareness17 of the value of the fossils. But these factors do not account for the interesting question of how there came to be such a concentration of pregnant ichthyosaurs in a particular place very close to their time of giving birth.
1 preservation
n.保護(hù)，維護(hù)，保存，保留，保持
參考例句：
The police are responsible for the preservation of law and order.警察負(fù)責(zé)維持法律與秩序。
The picture is in an excellent state of preservation.這幅畫保存得極為完好。
2 embryos
n.晶胚；胚，胚胎( embryo的名詞復(fù)數(shù) )
參考例句：
Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物體細(xì)胞進(jìn)入一個(gè)生殖階段，而且其行為象胚。 來自辭典例句
Evolution can explain why human embryos look like gilled fishes. 進(jìn)化論能夠解釋為什么人類的胚胎看起來象除去了內(nèi)臟的魚一樣。 來自辭典例句
3 juveniles
n.青少年( juvenile的名詞復(fù)數(shù) )；扮演少年角色的演員；未成年人
參考例句：
Do you think that punishment for violent crimes should be the same for juveniles and adults? 你對(duì)暴力犯罪的懲罰對(duì)于青少年和成人應(yīng)一樣嗎？ 來自生活英語口語25天快訓(xùn)
Juveniles Should we not exactly in need of such strength and conviction? 少年的我們難道不正是需要這種力量和信念嗎？ 來自互聯(lián)網(wǎng)
4 scattered
adj.分散的，稀疏的；散步的；疏疏落落的
參考例句：
Gathering up his scattered papers,he pushed them into his case.他把散亂的文件收拾起來，塞進(jìn)文件夾里。
5 marine
adj.海的；海生的；航海的；海事的；n.水兵
參考例句：
Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
When the war broke out,he volunteered for the Marine Corps.戰(zhàn)爭(zhēng)爆發(fā)時(shí)，他自愿參加了海軍陸戰(zhàn)隊(duì)。
6 suite
n.一套(家具)；套房；隨從人員
參考例句：
She has a suite of rooms in the hotel.她在那家旅館有一套房間。
That is a nice suite of furniture.那套家具很不錯(cuò)。
7 jumble
vt.使混亂，混雜；n.混亂；雜亂的一堆
參考例句：
Even the furniture remained the same jumble that it had always been.甚至家具還是象過去一樣雜亂無章。
The things in the drawer were all in a jumble.抽屜里的東西很雜亂。
8 treasury
n.寶庫；國庫，金庫；文庫
參考例句：
The Treasury was opposed in principle to the proposals.財(cái)政部原則上反對(duì)這些提案。
This book is a treasury of useful information.這本書是有價(jià)值的信息寶庫。
9 remains
n.剩余物，殘留物；遺體，遺跡
參考例句：
He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
The remains of the meal were fed to the dog.殘羹剩飯喂狗了。
10 shale
n.頁巖，泥板巖
參考例句：
We can extract oil from shale.我們可以從頁巖中提取石油。
Most of the rock in this mountain is shale.這座山上大部分的巖石都是頁巖。
11 shales
n.頁巖( shale的名詞復(fù)數(shù) )
參考例句：
Sandstones are, as a rule, interbedded with shales. 砂巖通常都與頁巖互層。 來自辭典例句
Oil-yielding organic matter is contained in the shales. 在這些頁巖里有產(chǎn)油的有機(jī)物質(zhì)。 來自辭典例句
12 specimen
n.樣本，標(biāo)本
參考例句：
You'll need tweezers to hold up the specimen.你要用鑷子來夾這標(biāo)本。
This specimen is richly variegated in colour.這件標(biāo)本上有很多顏色。
13 specimens
n.樣品( specimen的名詞復(fù)數(shù) )；范例；（化驗(yàn)的）抽樣；某種類型的人
參考例句：
Astronauts have brought back specimens of rock from the moon. 宇航員從月球帶回了巖石標(biāo)本。
The traveler brought back some specimens of the rocks from the mountains. 那位旅行者從山上帶回了一些巖石標(biāo)本。 來自《簡(jiǎn)明英漢詞典》
14 reptiles
n.爬行動(dòng)物，爬蟲( reptile的名詞復(fù)數(shù) )
參考例句：
Snakes and crocodiles are both reptiles. 蛇和鱷魚都是爬行動(dòng)物。 來自《簡(jiǎn)明英漢詞典》
Birds, reptiles and insects come from eggs. 鳥類、爬蟲及昆蟲是卵生的。 來自《現(xiàn)代漢英綜合大詞典》
15 invertebrates
n.無脊椎動(dòng)物( invertebrate的名詞復(fù)數(shù) )
參考例句：
Insects and worms are all invertebrates. 昆蟲和蠕蟲都是無脊椎動(dòng)物。 來自辭典例句
In the earthworm and many other invertebrates, these excretory structures are called nephridia. 在蚯蚓和許多其它無脊椎動(dòng)物中，這些排泄結(jié)構(gòu)稱為腎管。 來自辭典例句
16 quarry
n.采石場(chǎng)；v.采石；費(fèi)力地找
參考例句：
Michelangelo obtained his marble from a quarry.米開朗基羅從采石場(chǎng)獲得他的大理石。
This mountain was the site for a quarry.這座山曾經(jīng)有一個(gè)采石場(chǎng)。
17 awareness
n.意識(shí)，覺悟，懂事，明智
參考例句：
There is a general awareness that smoking is harmful.人們普遍認(rèn)識(shí)到吸煙有害健康。
Environmental awareness has increased over the years.這些年來人們的環(huán)境意識(shí)增強(qiáng)了。
The preservation1 of embryos2 and juveniles3 is a rate occurrence in the fossil record. The tiny, delicate skeletons are usually scattered4 by scavengers or destroyed by weathering before they can be fossilized. Ichthyosaurs had a higher chance of being preserved than did terrestrial creatures because, as marine5 animals, they tended to live in environments less subject to erosion. Still, their fossilization required a suite6 of factors: a slow rate of decay of soft tissues, little scavenging by other animals, a lack of swift currents and waves to jumble7 and carry away small bones, and fairly rapid burial. Given these factors, some areas have become a treasury8 of well-preserved ichthyosaur fossils.
The deposits at Holzmaden, Germany, present an interesting case for analysis. The ichthyosaur remains9 are found in black, bituminous marine shales11 deposited about 190 million years ago. Over the years, thousands of specimens13 of marine reptiles14, fish and invertebrates15 have been recovered from these rocks. The quality of preservation is outstanding, but what is even more impressive is the number of ichthyosaur fossils containing preserved embryos. Ichthyosaurs with embryos have been reported from 6 different levels of the shale10 in a small area around Holzmaden, suggesting that a specific site was used by large numbers of ichthyosaurs repeatedly over time. The embryos are quite advanced in their physical development; their paddles, for example, are already well formed. One specimen12 is even preserved in the birth canal. In addition, the shale contains the remains of many newborns that are between 20 and 30 inches long.
Why are there so many pregnant females and young at Holzmaden when they are so rare elsewhere? The quality of preservation is almost unmatched and quarry16 operations have been carried out carefully with an awareness17 of the value of the fossils. But these factors do not account for the interesting question of how there came to be such a concentration of pregnant ichthyosaurs in a particular place very close to their time of giving birth.
1 preservation
n.保護(hù)，維護(hù)，保存，保留，保持
參考例句：
The police are responsible for the preservation of law and order.警察負(fù)責(zé)維持法律與秩序。
The picture is in an excellent state of preservation.這幅畫保存得極為完好。
2 embryos
n.晶胚；胚，胚胎( embryo的名詞復(fù)數(shù) )
參考例句：
Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物體細(xì)胞進(jìn)入一個(gè)生殖階段，而且其行為象胚。 來自辭典例句
Evolution can explain why human embryos look like gilled fishes. 進(jìn)化論能夠解釋為什么人類的胚胎看起來象除去了內(nèi)臟的魚一樣。 來自辭典例句
3 juveniles
n.青少年( juvenile的名詞復(fù)數(shù) )；扮演少年角色的演員；未成年人
參考例句：
Do you think that punishment for violent crimes should be the same for juveniles and adults? 你對(duì)暴力犯罪的懲罰對(duì)于青少年和成人應(yīng)一樣嗎？ 來自生活英語口語25天快訓(xùn)
Juveniles Should we not exactly in need of such strength and conviction? 少年的我們難道不正是需要這種力量和信念嗎？ 來自互聯(lián)網(wǎng)
4 scattered
adj.分散的，稀疏的；散步的；疏疏落落的
參考例句：
Gathering up his scattered papers,he pushed them into his case.他把散亂的文件收拾起來，塞進(jìn)文件夾里。
5 marine
adj.海的；海生的；航海的；海事的；n.水兵
參考例句：
Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
When the war broke out,he volunteered for the Marine Corps.戰(zhàn)爭(zhēng)爆發(fā)時(shí)，他自愿參加了海軍陸戰(zhàn)隊(duì)。
6 suite
n.一套(家具)；套房；隨從人員
參考例句：
She has a suite of rooms in the hotel.她在那家旅館有一套房間。
That is a nice suite of furniture.那套家具很不錯(cuò)。
7 jumble
vt.使混亂，混雜；n.混亂；雜亂的一堆
參考例句：
Even the furniture remained the same jumble that it had always been.甚至家具還是象過去一樣雜亂無章。
The things in the drawer were all in a jumble.抽屜里的東西很雜亂。
8 treasury
n.寶庫；國庫，金庫；文庫
參考例句：
The Treasury was opposed in principle to the proposals.財(cái)政部原則上反對(duì)這些提案。
This book is a treasury of useful information.這本書是有價(jià)值的信息寶庫。
9 remains
n.剩余物，殘留物；遺體，遺跡
參考例句：
He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
The remains of the meal were fed to the dog.殘羹剩飯喂狗了。
10 shale
n.頁巖，泥板巖
參考例句：
We can extract oil from shale.我們可以從頁巖中提取石油。
Most of the rock in this mountain is shale.這座山上大部分的巖石都是頁巖。
11 shales
n.頁巖( shale的名詞復(fù)數(shù) )
參考例句：
Sandstones are, as a rule, interbedded with shales. 砂巖通常都與頁巖互層。 來自辭典例句
Oil-yielding organic matter is contained in the shales. 在這些頁巖里有產(chǎn)油的有機(jī)物質(zhì)。 來自辭典例句
12 specimen
n.樣本，標(biāo)本
參考例句：
You'll need tweezers to hold up the specimen.你要用鑷子來夾這標(biāo)本。
This specimen is richly variegated in colour.這件標(biāo)本上有很多顏色。
13 specimens
n.樣品( specimen的名詞復(fù)數(shù) )；范例；（化驗(yàn)的）抽樣；某種類型的人
參考例句：
Astronauts have brought back specimens of rock from the moon. 宇航員從月球帶回了巖石標(biāo)本。
The traveler brought back some specimens of the rocks from the mountains. 那位旅行者從山上帶回了一些巖石標(biāo)本。 來自《簡(jiǎn)明英漢詞典》
14 reptiles
n.爬行動(dòng)物，爬蟲( reptile的名詞復(fù)數(shù) )
參考例句：
Snakes and crocodiles are both reptiles. 蛇和鱷魚都是爬行動(dòng)物。 來自《簡(jiǎn)明英漢詞典》
Birds, reptiles and insects come from eggs. 鳥類、爬蟲及昆蟲是卵生的。 來自《現(xiàn)代漢英綜合大詞典》
15 invertebrates
n.無脊椎動(dòng)物( invertebrate的名詞復(fù)數(shù) )
參考例句：
Insects and worms are all invertebrates. 昆蟲和蠕蟲都是無脊椎動(dòng)物。 來自辭典例句
In the earthworm and many other invertebrates, these excretory structures are called nephridia. 在蚯蚓和許多其它無脊椎動(dòng)物中，這些排泄結(jié)構(gòu)稱為腎管。 來自辭典例句
16 quarry
n.采石場(chǎng)；v.采石；費(fèi)力地找
參考例句：
Michelangelo obtained his marble from a quarry.米開朗基羅從采石場(chǎng)獲得他的大理石。
This mountain was the site for a quarry.這座山曾經(jīng)有一個(gè)采石場(chǎng)。
17 awareness
n.意識(shí)，覺悟，懂事，明智
參考例句：
There is a general awareness that smoking is harmful.人們普遍認(rèn)識(shí)到吸煙有害健康。
Environmental awareness has increased over the years.這些年來人們的環(huán)境意識(shí)增強(qiáng)了。