XXXVlll GEOLOGICAL AND PALEOXTOLOGICAL RELATIONS 



diatoms from Maryland and Ehrenberg, in the same year enumerated 

 sixty-eight species from Piscataway and included many Miocene forms 

 among them. Kogers, in the same year, assigned the diatomaceous 

 earth to a position near the base of the Miocene. 



About this time much interest was created in the Miocene problem 

 of Maryland by Sir Charles Lyell. He regarded these deposits as 

 Miocene, and gave at some length his reasons for this opinion. He 

 also stated that the Miocene of Maryland agreed more closely with the 

 Miocene of Lorraine and Bordeaux than to the Suffolk Crag. Lonsdale 

 also concluded from the corals collected in the Miocene which 

 were submitted to him for examination, that the American deposits 

 were probably accumulated while the climate was somewhat " superior " 

 to that of the Crag and " perhaps " equal to that of the faluns of Lor- 

 raine but " inferior " to that of Bordeaux. In the same year Conrad 

 described and figured many fossils from the Calvert Cliffs. In the 

 year 1850 Higgins gave analyses of many samples of marl from Kent, 

 Talbot and Anne Arundel counties. It is probable that many of these 

 marls belong to the Miocene. 



No more papers of importance appeared on the Maryland Miocene 

 until 1863 when Dana brought out his first edition of the Manual of 

 Geology. In this work he took occasion to propose the term " York- 

 town epoch " for the period during which the Miocene of the Atlantic 

 coast was deposited. The next paper of significance was published by 

 Heilprin in 1881, in which he discussed the Miocene at some length, and 

 divided it into an " Older period " and a " Newer period." The Older 

 period contained the older portion of the Miocene of Maryland; and 

 the Newer period, the later portion. He subdivided the Newer period 

 again into the Patuxent Group and the St. Mary's Group. The next 

 year, the same author revised his classification and divided the Miocene 

 into three groups as follows: the Carolinian or the Upper Atlantic 

 Miocene including the Sumpter epoch of Dana, the Virginian or Middle 

 Atlantic Miocene including part of the Yorktown of Dana and the 

 Newer group of Maryland, and the Marylandian or the Older Atlantic 

 Miocene including the rest of Dana's Yorktown and the older period 

 of Maryland. He suggested that the Virginian was of the same age 



