June 11, 1909] 



SCIENCE 



941 



100 to 125 feet above the Upper Freeport coal. 

 From 60 to 90 feet above tbis is tbe Pine 

 Creek limestone, while the Ames limestone is 

 about 125 feet above the Pine Creek and 300 

 feet belov? the Pittsburg coal. Under various 

 names these limestones have been reported 

 from a large area in western Pennsylvania, 

 northern West Virginia and southeastern Ohio. 

 As these limestones are all very thin and are 

 included in a great mass of shales and sand- 

 stones of debatable origin, the discovery of 

 two more layers containing marine fossils is 

 of some interest. 



The first of the layers is about 50 feet below 

 the base of the Ames limestone on Brighton 

 Road, just west of Wood's Eun, Allegheny, Pa. 

 This stratum was noted by the writer in 1907, 

 but as it was found in only one place, it was 

 thought at the time that it might be a dis- 

 turbed block of the Ames limestone. It was, 

 however, mentioned in a paper just published 

 in the Annals of the Carnegie Museum, Vol- 

 xmie v., page 1Y4, and its correct stratigraphic 

 position indicated in the diagram on Plate 

 XII. As exposed at the type-locality on 

 Brighton Eoad, the fossiliferous layer is about 

 three inches thick and contains nimierous 

 crinoid stems, Producii, and cup-corals. It is 

 a hard clayey limestone, with most of the lime 

 leached out at the outcrop. It outcrops at a 

 number of places vrithin two miles of this 

 locality, but has not yet been traced to any 

 distance. At some of the other outcrops the 

 layer is thicker, the greatest thickness noted 

 being eighteen inches. 



In an article on the Conemaugh formation 

 in southern Ohio just published in the Ohio 

 Naturalist, Mr. D. Dale Condit describes a 

 thin marine limestone about haK-way between 

 the Ames and the Upper Cambridge lime- 

 stones. This limestone occupies the same 

 stratigraphic position as the one here de- 

 scribed, but as they are separated by a very 

 wide area in which neither has been sought, 

 it is too early to attempt to correlate the two. 



The credit for the discovery of the second 

 layer with marine fossils belongs largely to the 

 Rev. P. E. ISTordgren, of Duquesne, Pa., who 

 found loose blocks of fossiliferous shale along 



the railroad tracks about two miles west of 

 Duquesne. The writer was able to trace these 

 blocks to their source in a layer of green sandy 

 shale at the top of the Birmingham shale. 

 This layer is about 65 feet above the Ames 

 limestone. In the vicinity of Pittsburg the 

 Birmingham shale is a conspicuous formation 

 in the cliffs which border the rivers. It is 

 from 40 to 50 feet in thickness and the base 

 is about 25 feet above the top of the Ames. 

 At the base of the Birmingham there is always 

 a layer of very thin-bedded black shale, and 

 sometimes a coal which is supposed to repre- 

 sent the Elk Lick. Above this carbonaceous 

 layer are thin-bedded dark shales which con- 

 tain pinnules and stems of ferns, and numer- 

 ous Estherias and fish-scales. Higher up the 

 shales become lighter colored, often sandy, and 

 are very barren of fossils. The only fossils so 

 far found in these light-colored layers are a 

 few specimens of an Aviculopecten like A. 

 whitei, a shell which is often found associated 

 with fossil plants. At the top of the Birming- 

 ham there is an abrupt change in the color, the 

 upper 8 to 15 feet being a red fissile shale. 

 Just beneath the red shale, or sometimes a few 

 feet above the base of the shale, there is a 

 rather prominent layer of sandy shale which 

 has now been found to contain marine fossils. 

 The fossils are species of Productus, Allorisma 

 and other pelecypods, and Tainoceras occi- 

 dentale. Fossils have been found in this layer 

 in Riverview Park, Allegheny, below Kenny- 

 wood Park near Duquesne, at Glassport, at 

 Wilmerding and at East Pittsburg. It is most 

 fossiliferous at the locality discovered by Mr, 

 Nordgren below Kennywood Park, and that 

 should be considered as the type-locality. 



In Riverview Park Aviculopecten may be 

 found in a layer 25 feet above the layer just 

 described and a further search for fossils may 

 show that the Ames is far from being the last 

 marine deposit in western Pennsylvania. 



Percy E. Raymond 



Caenegie Museum, 

 May 7, 1909 



NEW FACTS ABOUT BACTERIA OF CALIFORNIA SOILS 



The bacteriological study of California soils 

 at this Experiment Station during the past year 



