1893.] MICROSCOPICAL JOURNAL. 165 



The brown chert is very compact. Init contains a few fragments 

 of shells, crinoid joints, and a number of light spaces, highly 

 crystalline, whose origin is to be traced to the replacement of or- 

 ganic life bv crystalline matter. 



The white chert is more abundantly fossiliferous even to the 

 naked eye, but under the microscope it is one mass of tossil lite, 

 crinoid stems being especially numerous. There are a number 

 of forms belonging to the group Porifera, or the order of sponges, 

 sponge spicules being found through the rock. 



Among all the sections there can be traced a great similarity. 

 The limestone, under the microscope, is seen to be quite uniform, 

 and confirms the observation made in the quarries that the abun- 

 dant and predominant forms are brachiopod shells. One section 

 showed the fossil vStyliola, a pteropod shell, which often forms 

 whole masses of Devonian limestone, but is very rare in Ohio 

 Devonian. 



The study of the carboniferous limestone is as yet incomplete, 

 but a number of new facts are coming to light, and certain lime- 

 stones long regarded as unfossilifeious are found to contain a 

 variety of fossil forms, only revealed by the microscope. 



The Tariff on Microscopical Boolvs. 



By CHAS. W. smiley, 



WASHINGTON, D. C. 



The effect of the tariff on books may be well understood from 

 the following prices of microscopical books published in England. 

 We give the I'etail prices asked by Messrs. Watson & Son, of 

 London, and the prices asked for the same books by one or more 

 American firms : 



Beale — How to Work with the Microscope. . 

 Cooke — i,ooo Objects for the Microscope, 

 Davies — -Moimting and Preparing Objects, 

 Griffith & Henfry — Micrographic Dictionary, 

 Hogg — The Microscope, .... 



Slack — Marvels of Pond Life, . . . . 



Wood — Common Objects for the Microscope, 



Total, 



This shows an average increase in price of 65 per cent. The 

 duty is only 25 per cent., but there are express charges, custom- 



