1897J MICROSCOPICAL JOURNAL. 179 



ject from a geologic standpoint. The letter was referred 

 to me for a reply, as I was supposed to be the only per- 

 son in Alabama that could give the information. 



At that date nothing was known of a fossil Marine 

 deposit of any kind, not even a fresh water fossil deposit 

 was known. We only had available the recent Marine 

 Diatoms of the Gulf and the likewise recent fresh water 

 sources. Since that date, the whole Diatom subject is 

 practically exhausted for this locality, and duly put upon 

 record for the benefit of the whole world. 



The writer of the letter proved to be Lewis Woolman, 

 of Overbrook, Pa., but latterly of Philadelphia, Pa., who 

 in connection or in collaboration with the Geological Sur- 

 vey of Pennsylvania, has been identified with the study 

 of water-bearing strata or horizons as determined through 

 the study of Artesian well borings and other sources. He 

 is also the originator of an hypotliesis involving the as- 

 sumption that, in the epoch in which the Miocene strata 

 were laid down or deposited, there was deposited along 

 the Atlantic Coastal area a series of Diatomaceous clays, 

 one stratum of which in particular represented by a de- 

 posit of at least 300 feet in thickness, and designated by 

 him the ''great 300 foot diatomaceous stratum." He had 

 reason to believe it might be traced somewhere all along 

 from New Jersey to the Florida peninsular, and sweep- 

 ing around to and occupying a portion of the Gulf of Mex- 

 ico Costal plain even into Alabama. 



It was with the object of collecting data to verify his 

 assumption, that he sought the aid of many correspon- 

 dents in securing material with which to establish the 

 truth of his hypotliesis. I rendered him every reasonable 

 assistance by furnishing specimens. By this means, I put 

 upon record at different periods, the important fresh wat- 

 er deposit of Montgomery, Ala., the fossil marine Dia- 

 tomaceous clay from the Tampa, Fla. phosphatic area, the 

 pyritized and mineralized diaotms of the Mobile, Ala., 



