374 ' Reports and Proceedings — 



Nearly all the Oolitic Limestones contain coral structures more or 

 less extensive ; in the Inferior Oolite were three distinct reefs super- 

 imposed on each other, having intermediate beds of Oolite rock ; the 

 Great Oolite had its reef; the Coral Kag possessed its reef; and the 

 Portland beds contained Zoophytic productions in like manner. 

 Now there was no doubt in the mind of any one who saw such a 

 rock as he (the lecturer) held in his hand but that it was a mass of 

 coral secreted by a Jurassic Zoophyte. But what was the roe-stone 

 or Oolitic rock which rested upon the reef? He submitted that it 

 was nothing more nor less than a portion of the wasted reef, which 

 had been broken and triturated and ground into mud ; that the paste 

 had coated particles of sand, and the whole had been cemented by 

 the calcareous waters and formed into the rock we call Oolitic 

 Limestone. For all these granules had a nucleus, and the cal- 

 careous globule was made up of a succession of laminae, as may 

 readily be seen in thin sections of the rock prepared for the 

 microscope. So the genesis of the Oolitic rocks was due to the vital 

 energies of the Zoophytes that lived in the Jui-assic seas. The 

 reefs that remained were mere fragments of those which had once 

 existed, and the reefs that had disappeared had furnished the 

 materials out of which the Oolites had been constructed. The same 

 explanation would apply to the Oolitic beds found in the Carboni- 

 ferous Limestone, which had been formed by the waste of the Coral 

 beds in the Carboniferous seas. But the Oolitic grains of the Carbon- 

 iferous Oolites had often a small foraminiferous shell as their nucleus, 

 instead of the particles found in the Jurassic Oolites ; but in both 

 cases the process of production was the same ; the granules had been 

 rolled along a shore and cemented into rock by a calcareous cement, 

 just as Oolitic beds are now in process of formation along the shores 

 of the coral reefs of our own day. There was only one true method 

 to interpret nature, and that was to watch how she proceeded in any 

 of her operations, and thus, having learned her modus operandi, to 

 explain the unknown by the known. There was another point 

 connected with this subject which the lecturer glanced at, namely, 

 the subject of geological time, which he illustrated by showing how 

 that all these reefs in the different Oolitic rocks had been built by 

 different species of Zoophytes, and as the life of individual species 

 was of long duration, as proved by the Zoophytes which construct 

 the reefs in the Gulf of Florida, so then the life of the species in the 

 Jurassic age, if they lived as long then as they do now, justified the 

 inference that the genesis of the Oolites was a very old and a very 

 long story indeed. Dr. Wright exhibited a beautiful enlarged draw- 

 ing by his friend Mr. Beach, who had prepared it from an illustration 

 by Professor Heer, showing the ancient physical geography of the 

 land with its plants and animals in the Jurassic sea. 



Dr. Wright was greeted on the conclusion of his address with 

 loud and hearty applause, and thanks were returned by the Presi- 

 dent and others for the new light which his explanation threw upon 

 the important question of rock formation — a problem which this 

 paper has done much to solve. 



