190 SYSTEMATIC PALEONTOLOGY 



Occurrence. CONOCOC-HEAGUE LIMESTONE. In Pennsylvania, Mary- 

 land, and Virginia this is a characteristic fossil at the hase of the Conoco- 

 cheague limestone. Specimens may be found at practically all of the 

 normal contacts between the Elbrook and Conococheague limestones. The 

 species is particularly abundant in the vicinity of Sharpsburg, Maryland, 

 and also in a cut of the Norfolk and Western Bailroad, one mile south- 

 west of Antietam Station where a reef of these algae is exposed. 



The original types came from the Ozarkian (Hoyt) limestone of Sara- 

 toga County, New York. 



Collections. Maryland Geological Survey, TJ. S. National Museum. 



CRYPTOZOON UNDULATUM n. sp. 

 Plate XXIX, Figs. 2, 3; Plate XXX 



Description. The Conococheague limestone in the Appalachian Valley 

 from Virginia to northeastern Pennsylvania and the corresponding strata 

 in New York State afford a second well-defined species of Cryptozoon 

 which occurs in association with C. proliferum. Comparison of the two 

 species will bring out the essential characters of the present new one. 

 Cryptozoon proliferum grows from a widely expanded almost flat series 

 of lamellae into numerous confluent heads of unequal size. In C.'undu- 

 latum the laminae are at first evenly undulating, forming in edge view, a 

 pseudo-columnar structure, the columns averaging 20 mm. in width. 

 A cross-section through this part of the fossil shows these column-like 

 areas to be of equal size and totally unlike the corresponding portion of 

 C. proliferum. Following the undulating zone in C. undulatum the 

 laminae go through a stage in which the distinct lamination disappears. 

 Then, with a new growth, the characteristic undulations of the species 

 reappear. 



Occurrence. CONOCOCHEAGUE LIMESTONE. Associated with Crypto- 

 zoon proliferum. The types are from a locality two and one-half miles 

 southeast of Funkstown, Maryland, where examples were numerous. 

 Sharpsburg and vicinity also show numerous specimens, particularly in 

 the stone fences. This species and C. proliferum have also been found 



