MACKIE— ON THE BOTTOM-ROCKS. 
189 
of Wicklow. It was there, however, nine years before Mr. Salter's 
discoveries in Shropsliiire, that the first relics of a primordial organized 
life were found by Dr. Kiuahan. 
Of those fossils doubtfully an animal or a plant, we are as yet only 
acquainted with one genus ; one species, the Oldhamia radiata* I 
lign. 4. — DiKEtocEPHAtus Minnesotensis. (Two-thirds nat. size.) From the Lowest Sand- 
stones, at Stillwater, Minnesota. (Reduced from the figure in Dr. Dale Owen's "Geological 
Report of Wisconsin, Iowa, and Minnesota.") 
have already figured in Vol. I. {see Frontispiece) in connexion with 
these papers. The other, and common form — for in these old Irish 
schists they exist in myriads, the scaling surfaces of the rocks bein 
completely bespattered with their elegant forms — I now present to 
my readers in Plate VIII. 
* Lately another peculiar and obscure form has been found, ffaughtonia. 
