GEOLOGY. 251 



communicated with 'submarine floors and dwindled down below. 

 Tlie mollusca, etc., of these seas were deposited in the fissures. 

 Three or four things were necessary to the formation of mineral 

 veins, — open crevices, the presence of certain minerals in the 

 water of the seas, and electrical action. Tiie Mendip hills are in- 

 tersected with veins, and on their tops some of these are worked. 

 One of them extends for 270 feet downwards, and contains 

 abundant lias fossils, although no liassic rocks are nearer than 

 several miles away. This proves how great must have been the 

 denudino: force. Mr. Moore has also discovered both land and 

 fresh-water shells in these veins, as well as entomostraca, as well as 

 seeds of old carboniferous plants. In the mines of North Wales 

 he had found molluscan and fish remains, the latter belonging to 

 no fewer than 10 genera. Intermixed with the contents of some 

 of the mineral veins, the author had found innumerable teeth of 

 fishes, conodonts, nearly all of which were so small that they re- 

 quired optical power to see them. In the lead veins he had met 

 with great quantities of foraminifera, all of secondary age. These 

 veins also developed the existence of a fresh-water fauna, of coal- 

 measure age, having no fewer than 9 genera, and 127 species. 



Mr. H. Brady said three well-known genera of foraminifera had 

 been mentioned by Mr. Moore, all of which still existed. One 

 of the most abundant of the foraminifera, Iii\jplutina, was remark- 

 able for its variety of form. Mr. Brady's remarks on the rest of 

 these minute shells were of a purely technical character. 



CHANGES IN THE DISTRIBUTION OF THE LARGE AMERICAN 

 MAIMMALS, THE SUBSTANCE OF SEVERAL COMMUNICATIONS 

 MADE TO THE BOSTON SOCIETY OF NATURAL HISTORY. BY 

 N. S. SHALER. 



In the course of some excavations made at Big Bone Lick, in 

 Kentucky, in the summer of 1869, some interesting information 

 was obtained concernino^ the fonner rang-e of several of our large 

 quadrupeds. The peculiarly uniform growth of the beds which 

 are con^tantly forming in this swamp, which is due to the depos- 

 its from the mineral springs, and to the regular accumulation of 

 sediment from overflows of the stream which passes through it, 

 enables us to measure, with tolerable accuracy, the relative age 

 of the several strata. 



The most important fact is, that the buffalo did' not begin to 

 come to these springs until a very recent day. It is impossible 

 to suppose that more than 500 years have elapsed since they 

 began to range into this part of the Mississippi valley. The 

 stratum in which their remains were found is the uppermost of 

 the bone beds, and is but two feet in thickness at the three points 

 where it was cut through ; beneath it was found the fragment of 

 an arrow-head of flint. The evidence of the recent appearance 

 of the butt'alo aflorded by the swamp at Big Bone Lick is corrob- 

 orated by that from a number of other sources. It seems fully 



