MARYLAND GEOLOGICAL SURVEY XClll 



grains of glauconite, which were in all probability formed in the Eocene 

 occur in the lower portions of the Miocene. 



The organic remains, which consist, for the most part, of shells of 

 moUusks and bones of vertebrates, are usually in a very good state of 

 preservation. They have been but slightly disturbed since deposited 

 and evidently now occupy the same relative positions which they did at 

 the time when they lived. 



Geological and Geographical Distribution of Species. 

 The geological and geographical distribution of the species obtained 

 from the Maryland Miocene has already been partly indicated in the 

 discussion of the various zones. A more complete presentation of the 

 occurrence of these forms is shown in the following tables as well as 

 in the chapters on S3'stematic paleontology. 



Note. — In a few instances forms have been described in the literature as 

 occurring at Maryland localities where members of the Maryland Survey 

 have not been able to corroborate their occurrence. In such cases their pres- 

 ence is indicated in the following tables by a * and a superior letter indi- 

 cating the authority. Thus: 

 ^ c Indicates an occurrence on the authority of Conrad. 

 ^ cp " " " " " " " Cope. 



^1 " " " " " " " Ball. 



" " " " Foreman. 



" " " " Say. 



" " " << Wagner. 



The few instances in which specimens have been described from the deep 

 well at Crisfield have been tabulated under " Crisfield well, St. Mary's Form- 

 ation (?)" since the uppermost members of the Miocene there exposed belong 

 to that formation and through possible accidents during the driving of the 

 well forms may have fallen in from the upper horizons and been recorded as 

 occurring at greater depth. The exact depths at which the forms were found 

 are given in the text and footnotes. The base of the Miocene lies about 776 feet 

 below the surface. 



