756 



SCIENCE 



[N. S. Vol. XL. No. 1038 



chert. Measurements of some of tlie beds were 

 taken in Providence Canyon and are shown in 

 the table below. 



At the top of the phosphate zone the rocks 

 are not sufficiently well exposed to afford de- 

 tailed study. A tunnel driven near the upper 

 limestone ledge shows a few inches of good 

 rock phosphate interstratified with dark- 

 colored limestone and shale. 



Thirty feet below this ledge twenty inches 

 of oolitic phosphate rock was measured and a 

 sample (No. 1) yielded 55 per cent. CajCPO^).. 

 In the next thirty feet below there are thin 

 bands of oolitic phosphate but none of them 

 are believed to be thick enough to be of econ- 

 omic value. The details of the lower part of 

 the bed in Providence Canyon follow: 



Per Cent 

 No. Kind of Work Ca2(PO)3 



3 feet dark gray limestone 



2 18 inolies phosphatie shale 30.10 



3 12 inches shaly phosphate rock 16.71 



4 48 inches dark shaly phosphate rock. . . 65.43 

 24 inches gray limestone 



"5 48 inches shale, some layers phosphatie. 14 



6 11 inches black shale 8.41 



7 30 inches shale, oolitic phosphate, in 



bands 21.30 



24 inches sandy limestone 



9 38 inches phosphate rock, shaly . . . . 33.01 



18 inches chert 



12 inches black shale 



10 30 inches phosphate rock 35.83 



11 12 inches phosphate rock 46.34 



2 inches black chert 



12 48 inches black shale 3.91 



6 inches black chert 



13 21 inches black oolitic phosphate rock. . 65.76 



1 inch black chert 



14 12 inches black shaly phosphate rock. . 21.40 



15 18 inches brown oolitic phosphate rock. 68.59 



bedding planes 28.31 



6 inches shale 



16 6 inches shale showing phosphate in. 



2 inches chert 



17 4 inches shaly phosphate rock 27.12 



20 inches sandy limestone 



IS 18 inches brown oolitic phosphate rock. 66.9 



12 inches black shale 



16 inches black shale with bands of 



chert 



5 inches brown oolitic phosphate rock. 52.22 



7 inches shale 



2 inches oolitic phosphate rock with 



much hematite 



Limestone ledge 



The samples for analysis were taken only 

 two or three feet under the surface and it 

 seems quite probable that they have been con- 

 siderably leached for the rock is less firm and 

 crumbles more easily than that from the upper 

 Pennsylvanian or Permian horizon. No 

 sampling has been done below the level to 

 which roots penetrate. It is thought the 

 amount of phosphate may decrease to some ex- 

 tent with depth, owing to the leaching of tht 

 less soluble constituents and the concentration 

 of the phosphoric acid in the leached zone. 



One very noticeable feature in the phosphate 

 zone in this locality, which is an aid in tracing 

 the phosphate, is that usually the growth of 

 vegetation is denser along the line of outcrop 

 than elsewhere. On hillsides which face the 

 south and, therefore, have but little moisture 

 or vegetation, growths of wild cherry, maple, 

 and aspen extend along the outcrop. As a few 

 small seeps and springs issue from the phos- 

 phate shales the denser vegetation there should 

 perhaps be partly accounted for by the 

 moisture. 



At a place four miles north of the locality 

 in Providence Canyon where the samples men- 

 tioned were obtained, two other samples were 

 taken from separate layers of oolitic phosphate 

 rock near the lower part of the deposit. The 

 sample from one bed 18 inches thick yielded 

 55.21 per cent, tricalcium phosphate.* The 

 other sample from a bed 42 inches thick yielded 

 61.32 per cent, of the material. The section 

 does not seem to agree in detail with the 

 measurements made in Providence Canyon. 

 It is thought by the writer that the Mississip- 

 pian rocks are sufficiently rich in tricalcium 

 phosphate to warrant investigation as to their 

 economic value. William Peterson 



Department op Geology, 

 Utah Agricultural College 



3 The analyses were mostly made by Mr. C. T. 

 Hirst in the Experiment Station chemical labora- 

 tory. 



