322 



limited to a general and vague result. Even when corresponding 

 fossils would seem to mark a simultaneous origin, we must not 

 forget the large agency of migration, and the long lapse of years 

 which in many cases may have been required for the extension of 

 a living race into distant submarine settlements. 



Prof. W. B. Rogers referred to some observations 

 communicated to him by Mr. L. W. Bailey, in relation 

 to an interesting locality of Diatomacese, at Oaklands, 

 North Providence. From an examination of the spot, 

 Mr. Bailey has furnished the following brief descrip- 

 tion : — 



" The locality is a pond of several hundred feet in circum- 

 ference, in a natural basin somewhat enlarged, lying to the east- 

 ward of the dwelling of Mr. A. Eaton, on whose estate it is 

 situated, and who was the first, I believe, to notice the deposit. 

 Near the side of the pond are several constant springs running 

 into it, and in the vicinity of these we find a white, soft earth, 

 which, on examination, proves to be entirely composed of the 

 siliceous epiderms of Diatomaceae. 



" It was late in the winter when the deposit was first pointed 

 out to me, and even at that inclement season I found living 

 Diatoms quite abundant in the pond, of the some character, for 

 the most part, as that of the fossil bed. At the present time, 

 (May,) the pond is very rich in specimens of all the forms repre- 

 sented in my drawings, besides many beautiful Desmideae, Con- 

 fervas, and Infusoria of every description. 



" As to the extent of the deposit, I have been able to learn but 

 little, owing to the depth of the pond, the abrupt descent of its 

 bank, and the general swampy character of the ground. The 

 layer of Diatoms crops out distinctly at only one point, where it 

 is several feet thick ; but from various facts I should infer that 

 the deposit extends over a space much larger than the present 

 area of the pond. The surrounding field of ploughed land is filled, 

 at some distance from the pond, with small white and powdery 

 lumps, probably upturned by the plough, which, under the micro- 

 scope, are found to be made up entirely of the same forms as the 

 pond deposit. 



