BUFFALO SOCIETY OF NATURAL SCIENCES 1 45 



everywhere and as Schmidt puts it, "In the extent of a single | 

 verst one may here lay out places for eurypterid quarries to one's 

 heart content" (248, 29). 



Above the plattenkalk ho~izon is a brecciated limestone of no great 

 thickness consisting of angular or slightly rounded fragments of com- 

 pact limestone in a matrix of similar limestone which contains Cala- 

 mopora polymorphs. The breccia is not derived from the underlying 

 dolomite, according to Schrenk (254, 47). This physical evidence 

 of a break at the top of the eurypterid dolomite has been more fully 

 described from other localities, as, for instance, at Wita, the section 

 next to be considered. 



To the southwest of Rootzikiill is the village of Wita. Here in 

 the yellowish white dolomite which is the characteristic eurypter id- 

 bearing fades two quarries have been opened. It was found that 

 the eurypterids occurred not only in the dolomite, but also at a higher 

 horizon in a brecciated coral limestone which is made up of angular, 

 sometimes rounded white nodular masses which are for the most 

 part corals lying embedded in a uniform, yellow, marly limestone 

 matrix. Schmidt (241, 167, 168) 'would correlate this bed with the 

 Burgsvick oolite of Gotland, the formation which there marks the 

 break between the upper and lower Gotlandian. The limestone at 

 Wita is only one foot thick; in its upper part it contains Leper ditia 

 baltica, Turritella obsoleta (= Holopella obsoleta), Spirifer elevatus, and 

 certain corals, all being characteristic of the Upper Ludlow of England 

 and of the Upper Gotlandian of Gotland. In the lower portion of 

 the breccia occur: Cephalaspis verrucosus, C. schrenkii, Eurypterus 

 Hscheri, Bunodes lunula, a new crustacean Dithyrocaris ? sp., Ortho- 

 ceras bullatum ?, Lingula nana, and Palceophycus acicula, besides many 

 fragments of crustacean claws, segments of walking legs and the like. 

 The section is of importance for three reasons: (1) There is physical 

 evidence of a break at the end of Wenlock or Lower Ludlow time, 

 marking a retreat of the sea. It did not return until Upper Ludlow 

 time as indicated by the presence of fossils of that age in the matrix of 

 the brecciated limestone. (2) The eurypterids occur abundantly in the 

 beds deposited immediately after the normal marine conditions ended, 

 while the sea retreated, and at the time when dry land was being 

 enlarged and consequently rivers were extending their distal por- 

 tions. (3) The eurypterids are also sparingly found in the breccia 

 and conglomerate which marks the return of the sea and renewed 

 deposition of marine sediments with marine organic remains. (4) 



