192 



Dr. Carpenter's Preliminary Report [Dec. 17' 



" coccoliths " of Prof. Huxley and the " coccospheres " of Dr. Wailich with 

 bodies observed in Chalk. While the soundings, on the nature of which 

 this conclusion was based, could not indicate more than the existence of a 

 mere surface-layer of this material, the fact that our large dredges came 

 up completely filled with it, and the manner in which massive Siliceous 

 Sponges had obviously been imbedded in it, clearly prove it to pos- 

 sess considerable thickness. The existence of this deposit over a very 

 large area was marked out by our Dredgings at the extreme distance of 

 200 miles, and by several intermediate Soundings ; and the variations in 

 its character corresponded closely with those which present themselves in 

 different parts of the same stratum of Chalk. 



VII. But besides confirming the views already promulgated, as to the 

 complete dependence of this Calcareous deposit on the enormous develop- 

 ment of low forms of Organic Life, our researches also show that the area 

 over which this deposit is being formed is peopled by a variety of higher 

 types of marine Animals, many of which carry us back in a most remark- 

 able manner to the Cretaceous epoch. Thus among Mollusca we have two 

 Terebratulidce,of which one at least (Terebratulina caput-serpentis) may be 

 certainly identified with a Cretaceous species, whilst the second ( Waldheimia 

 cranium) may be fairly regarded as representing, if not lineally descended 

 from, another of the types of that family so abundant in the Chalk. Among 

 Echinoderms we have the little Rhizocrinus, that carries us back to the 

 Apiocrinite tribe which flourished in the Oolitic period, and was until lately 

 supposed to have had its last representative in the Bourgetticrinus of the 

 Chalk, to which the Rhizocrinus presents many points of remarkable cor- 

 respondence *. Among Zoophytes, the Oculina we met with in a living 

 state seems generically allied to a Cretaceous type (O. explanata of Miche- 

 lin). And the remarkable abundance of Sponges, which not improbably 

 derive their nutriment from the protoplasmic substance that enters largely 

 into the composition of the calcareous mud wherein they are imbedded 

 (p. 190), is a preeminently conspicuous feature of resemblance. — We can 

 scarcely doubt that a more systematic examination of the remarkable 

 Formation at present in progress would place in a still stronger light 

 the relationship of its Fauna to that of the Cretaceous period, since the 

 specimens w r hich our few dredgefuls contained can only be considered as a 

 mere sample of the varied forms of Animal life which this part of the 

 Ocean-bottom sustains. And if our notion of the intimacy of this rela- 

 tionship should be confirmed by further inquiry, it would go far to prove, 

 what seems on general grounds highly probable, that the deposit of Globi- 

 gerina-mud has been going on, over some part or other of the North- Atlantic 

 sea-bed, from the Cretaceous epoch to the present time (as there is much 

 reason to think that it did elsewhere in anterior Geological periods), this 

 mud being not merely a Chalk-formation, but a continuation of the Chalk- 



* See the recently published " Memoires pour'servir a la connaissance des Crinoides 

 vivants," by Prof. Sars (Christiania, 1868). 



