June 14, 1895.] 



SCIENCE. 



G57 



ing curved ami nearly triangular. Wlieu 

 put into pure water, it invariably showed 

 a slight acidity, reddening blue litmus pa- 

 per. It can be taken from the deposit in 

 lumps ; but they readily fall to powder, the 

 particles or flakes becoming separated by the 

 pressure of one's hand. During a tour 

 through southern Utah in the j'ear 1S93 I 

 found another large deposit of the same 

 kind of volcanic product on the east side of 

 the Wasatch Mountains in the vicinity of 

 Jlonroe village, in Sevier county. I could 

 find no dift'erence between this latter and 

 that whicli occurs near Stockton. Both 

 give a slight acid reaction, which, I suspect 

 to be due to a sulphur compound. 



In the same j^ear, 1893, there was brought 

 to me a good sample of grayish white, strati- 

 fled mineral substance, said to be kaolinite 

 and to have been taken from an immense 

 deposit of a similar character east of Green 

 River and in northwestern Colorado. This 

 so-called * kaolinite' proved upon examina- 

 tion to be similar A'olcauic dust, which had 

 been subjected to the action of water mixed 

 with clay, deposited in layers under the 

 water, and afterwards hardened. 



Hexrt Moxtgomert. 

 tmxity uxiveesity, toronto. 



volca>"ic dust ix texas. 



UxDER the above title Jlr. H. W. Turner 

 contributes an article to Sciexce of April 

 2G, 1895, briefly describing a specimen 

 from the Llano Estacado region. Some of 

 the previous notices of this or similar ma- 

 terial are noted below. 



The flrst specimen of the material which 

 came under mj' notice was received by the 

 Texas Survey in February, 1890, with other 

 material forwarded by Professor "W. F. 

 Cummins. It was collected from the beds 

 to which he gave the name ' Blanco Can- 

 yon ' from the place of their most char- 

 acteristic development, and in his fii-st de- 



scription of tliem* he calls it chalk. 

 Later, microscopic slides of this material 

 were prepared in the Survey laboratory, bj' 

 ilr. J. S. Stone, under the dii-ection of Pro- 

 fessor R. T. Hill, and these exhibited a 

 large number of very finely prt-served 

 diatoms. 



These diatoms were pai-tially identified 

 by Mr. C. H. Kain and pul)lished by Prof. 

 Cope in his flrst notice of the probable 

 Pliocene age of the Blanco Canyon beds.f 



The diatomaceous character of this ma- 

 terial was further noted by Messi-s. Lewis 

 "Woolman and C. Henry Kain, and list of 

 species given in The American Xafuraligt for 

 1892, p. 505, under the title ' Fresh-Water 

 Diatomaceous Deposit from Staked Plains, 

 Texas.' 



In 1892 an examination of this material 

 by the WTiter showed the presence of vol- 

 canic dust, but the diatoms constituted bj' 

 far the greater part of the mass examined, 

 and it was tlierefore classed with other ma- 

 terials of a similar kind from the coast 

 region as diatomaceous earth, and only 

 tho.se siliceous deposits of like character 

 which failed to reveal diatoms were classed 

 as volcanic dust and Ijriefly descrilied in 

 the Transactions of the Texas Academy of 

 Science. J Further reference to these sili- 

 ceous deposits are also made by Kennedy 

 in the Fourth Annual Report Geol. Sur. 

 Texas, pp. 20, etc. 



The stratigrajiliic position of tlie depo.sit 

 referred to liy Mr. Turner has been accu- 

 rately determined, as will l.)e seen liy refer- 

 ence to the difl'erent reports of Professor 

 Cummins on northwest Texas and the 

 Llano Estacado. The hill mentioned, ou 

 Duck Creek, in Dickens county, is in the 

 type locality of the Blanco Canyon beds, 

 and sections are given of it iu the first three 



* First Mm. Rep. Geol. Sur. Te.\as, p. 190. 

 t Proc. Amer. IMiil. .Soc., 1892, p. 123. 

 J Vol. I., Part I., 1892. P. 33. 'Volcanic Duat 

 in Texas.' 



