78 . JOURNAL OF THE [July, 



in a limestone ledge, and on the edge of the crevice, where the 

 water ran through, I scraped off the dark sHme and examined it 

 when 1 arrived home. 



"In looking over my slides I found one put up by J. D. 

 Moller, marked ' Terpsinoe nmsica Ehr. A. dulce, Porto Rico,' 

 showing that at that date it was known as a fresh-water diatom. 



''I find only one slide in my collection, a very poor one, put 

 up by me in 1883, which I forward with this. Your members 

 can compare it with the Cunningham mount. I would like to 

 know if it differs from his." 



The Corresponding Secretary also read a communication from 

 Mr. K. M. Cunningham, dated Mobile, x\labama, February 24th, 

 1893, as follows : 



" The information in your favor of the 20th instant suggests, 

 the propriety of my stating upon what ground I reported the 

 diatomaceous clay of miocene age. 



" In effect, possibly eight years ago, and also at a later period, 

 Mr. Lewis Woolman. of Overbrook, Pa., member of the Phila- 

 delphia Academy of Sciences, opened a correspondence with me 

 to secure my assistance in collecting material to aid his geological 

 inquiries. He intimated that he had a theory which he desired 

 to verify — namely, that the great diatomaceous stratum of 300 

 feet, more or less, in thickness, studied by him as underlying 

 New Jersey, Maryland, and Virginia, would possibly be found 

 existing on the Gulf coast — and that he had special reasons for 

 holding this theory. After several years nothing confirmed his 

 hopes until I communicated to your Society and to him the 

 occurrence of the polycystinous, diatom, and foraminiferal clay 

 stratum at St. Stephens, Alabama. This fact renewed his hopes, 

 and, while the clay was associated with undoubted eocene strata, 

 it was not what he desired to corroborate his hypothesis. He 

 wanted a clay of miocene age, which the former was not. 



"Next I followed the subject through the boring of several 

 artesian wells at Mobile, and sent him the micro-fossil organic 

 evidence of the strata encountered at 700 feet — the foraminifera, 

 and a special minute bivalve whose specific name is still in con- 

 troversy — indicating that the pyritized marine diatoms found in 

 the clay were of pliocene age. So to this point we had not 

 reached a miocene clay. 



