MARYLAND GEOLOGICAL SURVEY 501 



south of Chesapeake E. E. Bridge. Found also in the Barbadoes deposit 

 and at Moron, Spain, Trinidad, and JSTicobar Islands. 

 Collection. — Maryland Geological Survey. 



Craspedodiscus elegans Ehrenberg. 



Plate CXXXV, Fig. 4. 



Craspedodiscus elegants Ehrenberg, 1844, Monatsb. d. k. Akad. d. Wiss., Berlin, p. 266. 

 Craspedodiscus elegans Bailey, 1845, Amer. Jour. Sci., vol. xlviii, pL iv, fig. D. 

 Craspedodiscus elegans Ehrenberg, 1856, Mikrogeologie, pi. 33, xviii, fig. 3. 

 Craspedodiscus elegans Ralfs, 1861, Pritchard's Infusoria, p. 832. 

 Craspedodiscus elegans Schmidt, 1875, Atlas der Diatomaceen-kunde, pi. Ixvi, fig. 1. 



Description. — Valve circular with well-defined border equal in width 

 to one-fourth the radius, its markings quadrate in oblique rows 1^ in 

 .01 mm. Central part undulating, markings hexagonal, 2 to 3 in .01 mm., 

 larger at the center and near the semi-radius, rather coarsely punctate 

 as are those of the border. Diam. .300 mm. 



This appears to be exclusively a Maryland form found only in the 

 lower or " Nottingham " ' deposit, where, however, in certain cleanings, 

 it is rather common. 



Occurrence. — Calvert FoRMATioisf. 1 mile east of Marriott Hill, 

 1 mile south of Chesapeake E. E. Bridge, 1 mile north of Jewell. 



Collection. — Maryland Geological Survey. 



2 Note on the "Bermuda" deposits. Professor J. W. Bailey of the U. S. Military 

 Academy at West Point, published in Silliman's Journal, in 1845, an article entitled 

 "Notice of Some New Localities of Infusoria, Fossil and Recent." On page 323 

 one of the localities is referred to as the "Bermuda Islands", certain material 

 labelled " Tripoli from Bermuda" having been received from a correspondent, Mr. 

 Tuomey. Professor Bailey believed that the deposit probably came from the Ber- 

 muda Islands, although he says that it is "remarkable that a deposit so silicious 

 could be found among the coralline isles of Bermuda", and he sent a quantity of the 

 earth to Ehrenberg who published in the Monatsberichte of the Berlin Academy in 

 1844 numerous descriptions of new genera and species which he had found. The 

 locality given by Bailey and Ehrenberg, in mistake, has been, and still is, repeated 

 so often by European diatomists that it may be well to state that a complete expla- 

 nation has been given in the American Journal of Microscopy, (1877), pp. 141 and 

 157. It has been suggested that a district known as Bermuda Hundred, in Virginia, 

 not far from Richmond, was the locality intended, but several observers have claimed 

 that no such deposit occurs there. The conclusion has been reached that the mate- 

 rial received by Bailey, containing, as it does, so many characteristic forms, must 

 have come from Maryland. Certain of the forms are found nowhere else, not even 

 in the Richmond deposit. Conspicuous outcrops occur near the village of Notting- 

 ham on the Patuxent river and the author is of the opinion that Bailey's and Ehren- 

 berg' s material came from this point. 



