192 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Either base or camera can be moved at will up or down the 

 vertical rod. Another type of camera which is of great value, 

 especially for larger fossils, is the one shown in figure 2. 



Prints made from the negative are often used for illustra- 

 tion, but in case the photograph is not clear enough for publi- 

 cation, outlines are taken either from the print or from the 

 negative. The fossil is then placed, with the coating of am- 

 monium chloride still adhering, under a Zeiss binocular where, 

 under magnifications of from 8 to 50 diameters, the characters 

 of the fossil are studied in connection with the photographic 

 print. The lower magnification was found to be the best in 

 most cases, for no object is even slightly distorted by this 

 magnification, and the structures stand out with surprising 

 clearness and beauty. This is especially true when the light 

 from a fifty-candlepower electric lamp is cast obliquely on the 

 fossil while under observation. In cases of finer structures, 

 such as the muscular fibers in the body wall of Tuditanus 

 ivalcotti, under the 50-diameter magnification, the light was 

 indispensable. On the outlines made from the photographs the 

 details of structure are put in while the object is still under 

 observation with the binocular, so that the chances of error 

 have been reduced to the minimum. 



The above remarks apply especially to the fossils from the 

 Linton, Ohio, coal measures and those from the Cannelton 

 slates. The Mazon creek nodules are very simply studied for 

 they are usually clearly preserved, but the Zeiss binocular was 

 found of the greatest service. The bones in the Mazon creek 

 specimens have all been transformed into kaolin. The bones, 

 in some instances, have been removed and wax casts made of 

 the impressions. This method was used by Doctor Hay (4) in 

 studying a specimen of Amphibamus grandiceps, and I have 

 found it very useful. 



