Professor R. Burckhanlt — Triassie Stcaifishes. 3 



IT. — Note on certain Ijipressions of Echinoder^is observed on 

 THE Sandstone Slabs in which the Skeletons of HyperO' 



BAPEDO.V GORDOXI AND BhYNCBOSAURUS ARE DRESERVED. 

 iBy Prof. Rudolf Bukckhaiidt, rii.D., of the University of Basel, Switzerland. 



WHEX searching for traces of the dermal structure preserved 

 in the specimen of Eyperodapedon in the British Museum 

 (Natural History) in London/ my attention was drawn to certain 

 spots where the matrix showed projections and pits of a polygonal 

 shape, whicli I detected when I took the photographs of this Triassie 

 reptile. Primarily occupying myself with the matrix of the principal 

 slab, in which the skeleton is enclosed, I quite thought I had only 

 to deal with dermal structures similar to those discovered in 

 lilujncliosaurus. 



One of these spots, lying between the ninth and tenth ribs of the 

 left side, particularly attracted my attention. This I was at first 

 inclined to regard as a dermal ossification, the pentagonal chai'acter 

 of which was unquestionable. On closer insj^ection I found, 

 however, the whole of the matrix densely covered with similar 

 structures, a circumstance which became still more perplexing in 

 proportion as I discovered their immense numbers, which were 

 equally abundant at a considerable distance from the body, and also 

 in the matrix of the counterpart which had not been touched by the 

 chisel. The matrix of the Ehynchosaurian fossils from Warwickshire 

 also showed the same character ; indeed, I found some on these slabs 

 in even better condition of preservation. 



^ ,^ . - 7 < '^ ^ 



^-M^ 







Prints of EdurnHkun^ \n tlie Tru^-iL S iml-t>me^ dI Win\itk--hne and Elgin. 

 From a specimen in the British Museum (Natural History), x 3. 



Actual petrefactions they were not, but simply the hollow 

 impressions leaving a film behind, between the coarse grains of the 

 sand. In size they vary between 3 mm. and 3 cm. in diameter. 

 The matrix is crowded with these bodies, which are deposited over 

 each other, all of them lying in the same plane as the skeleton of 



^ See " On H>/pcrod<'pcdon Gordoni " : Geol. Mag., 1900, Nov. and Doc. 



