176 THE POPULAR SCIENCE MONTHLY. 



Palteozoic ocean ; while the formation of those beds of vast area, in 

 which few or no traces of animal life are found, may be fairly referred 

 to the agency of minute forms, essentially similar to those of the 

 Old Chalk and of its existing representative (Globigerina-mud), whose 

 habitation is the deep sea. 



No inconsiderable proportion of the calcareous material of some 

 of the local beds seems to have been furnished by the stems and 

 bodies of the Crinoids (lily-like animals), which abounded in the 

 Palaeozoic seas, and of which the representatives at the present time 

 have been proved by recent deep-sea exploration to be much more 

 numerous and widely diffused than was previously supposed. I re- 

 member to have seen these very conspicuous in polished sections of 

 the old " black rock ; " and certain beds in tlie limestone of Derby- 

 shire, which are worked for marble chimney-pieces, seem almost en- 

 tirely composed of their remains. The stems of the Crinoids of the 

 Carboniferous period were not beaded like those of the Dudley (Silu- 

 rian) limestone, but were cylindrical in form ; they had, however, the 

 same jointed structure and central canal ; and you will thus readily 

 recognize them when cut either longitudinally, transversely, or ob- 

 liquely. 



It has been further recently shown that Polyzoa essentially re- 

 sembling those of our modern " coralline crag" existed at this epoch, 

 and had a share in the formation of certain beds of the carboniferous 

 limestone. There is a particular bed in St. Vincent's rocks, which has 

 been found by Mr. Stoddart to be composed of fragments of their 

 delicate calcareous fabrics, with Foraminifera, and other small forms 

 of animal life ; and he has appropriately named it the microzoic bed. 

 And Prof. Young, of Glasgow, has been fortunate enough to find, in a 

 clay-seam of the carboniferous limestone in his neighborhood, a col- 

 lection of these fabrics preserved entire in the fullest perfection. 



Thus we seem justified in the conclusion that the vast strata of 

 carboniferous limestone, which in England alone must cover tens of 

 thousands of square miles, and has a thickness of more than two 

 thousand feet, had their sole origin in the continuous life of innumer 

 able generations of humble animals, which, in times long past, did 

 the work that is still being performed in the dej^ths of our own seas 

 by animals of similar types, which we may believe to be their lineal 

 descendants. I have shown you how we are indebted to their agency 

 for the abundant supplies they have provided of a material most 

 useful I may say indispensable to us. Let us take care that, with 

 our larger capacities and higher aims, we strive to promote the wel- 

 fare of those who come after us, by doing well, each in his station, 

 that which our powers and opportunities best fit us to accomplish. 

 Author's advance-sheets. 



