506 Geological Society. 



connexion with some facts recorded by the author in a former me- 

 moir; namely, that many structures, including blood-vessels, have their 

 origin in rows of cells derived from corpuscles of the blood. The hu- 

 man spermatozoon presented a disc with a pellucid depression, each 

 of the two sides of the peripheral portion of which was extended into 

 a thread ; these two threads forming by being twisted the part 

 usually designated as the tail. The occurrence of two tails, observed 

 by Wagner, is accounted for by the author by the untwisting of these 

 threads. 



The author has noticed very curious resemblances in mould, arising 

 from the decay of organic matter, to early stages in the formation of 

 the most elaborate animal tissues, more particularly nerve and muscle. 

 Flax has afforded satisfactory evidence of identity, not only in struc- 

 ture, but in the mode of reproduction, between animal and vegetable 

 fibre. 



• Valentin had previously stated that in plants all secondary deposits 

 take place in spiral lines. In the internal structure of animals, spirals 

 have heretofore seemed to be wanting, or very nearly so. Should 

 the facts recorded in this memoir, however, be established by the re- 

 searches of other investigators, the author thinks the question in fu- 

 ture may perhaps be, where is the " secondary deposit " in animal 

 structure, which is not connected with the spiral form ? The spiral 

 in animals, as he conceives he has shown, is in strictness not a se- 

 condary formation, but the most primary of all ; and the question 

 now is, whether it is not precisely so in plants. 



In a postscript the author observes, that there are states of volun- 

 tary muscle in which the longitudinal filaments (" fibrillse") have no 

 concern in the production of the transverse striae ; these striae being 

 occasioned by the windings of spirals, within which very minute 

 bundles of longitudinal filaments are contained and have their origin. 

 The spirals are interlaced. When mature, they are flat and grooved 

 filaments, having the compound structure above described. With 

 the shortening of the longitudinal filaments (" fibrillse") in muscular 

 contraction, the surrounding spirals, and of course the striae, be- 

 come elongated and narrow ; while in relaxation these changes are 

 reversed.* 



GEOLOGICAL SOCIETY. 



April 7, 1841. — " A note by Mr. Murchison on a Section and a 

 List of Fossils from the State of New York," by James Hall, Esq., 

 was read. 



Mr. Murchison says, that in consequence of the researches of Mr. 

 Featherstonaugh, Mr. Conrad, Mr. Hall, Mr. Vanuxem, Mr. R. C. 

 Taylor, and other geologists, large tracts in the British colonies in 

 North America and in the United States have been for some time 

 known to be composed of formations containing Silurian, old red 

 sandstone and carboniferous fossils. Mr. Hall's section, presenting 

 a tabular view of the succession of formations, commences with the 



[* We learn that the author has satisfactorily demonstrated to Professor 

 Owen and others, since the reading of the above paper, the facts described 

 in it. — Edit.] 



