Trans. N. V. Ac. Scz. 84 Jan. 9, 



that the most deHcate marine organisms are beautifully preserved. In 

 places the Trenton limestones abut directly against the Laurentian 

 clitis which formed the shore, and which suffered so little wear that 

 they contributed scarcely anything to the organic sediment deposited at 

 their base. This record hardly requires translation to be understood 

 by all, and its antagonism to the proposed theory is apparent and irre- 

 concilable. 



Toward the close of the Lower Silurian age, the sea slowly retreated 

 from the land it had before invaded, forming wide areas of shallow 

 water in which grew countless numbers of sea-weeds and delicate 

 graptolites, the carbonaceous matter of which, mingling with a finf. 

 wash from the land, produced the bitummous clays which we now call 

 the Utica slate. It is evident that the organisms which supplied the 

 combustible matter of this deposit could only have lived in quiet lagoon- 

 like bays, and their presence and product, with the fineness of the inor- 

 ganic sediment, are incompatible with Prof. Ball's theory. 



Similar phenomena teach the same lesson in the records of the Devon- 

 ian, Carboniferous, and later geological ages. In the Devonian rocks 

 we have another and apparently conclusive argument against extraor- 

 dmarily high tides, for here are coral reefs, rivaling in extent those of 

 the tropics at the present day. Now unless the reef-building polyps 

 were formerly altogether different m habit from those now living, these 

 coral reefs must have been formed in water not exceeding two hundred 

 feet of average depth and not subject to great oscillations of level. 

 High tides would now effect the rapid destruction of the whole race 

 of reef-buildirg animals ; at the ebb exposing them to the air and sun 

 for hours, and at the flood burying them too deeply for their continued, 

 existence. 



The abundant sea-weeds buried in the rocks of the Pateozoic and 

 later ages, offer an equally strong argument against the high-tide theory. 

 Nearly all the sea-weeds uonv living in our oceans occupy the immediate 

 shore, and chiefly grow within a depth of from 50 to 100 feet from high- 

 water mark. It is easy to see that if the present oceans were affected 

 by a movement like that described by Prof. Ball, the zone the sea-weeds. 

 occupy would be the scene of the grea'est mechanical violence, and 

 they would be alternately left to dry in thesun,. or be torn with resistless 

 force from their anchorage and scattered over the land washed by the 

 flood tide. On every old beach, however, of which we find so many in 

 the geological series, the casts of the fronds and stems of sea-weeds 

 are as plainly discernible as on our present shores. 



In view of these facts, and others of similar import which might be 

 cited, we are compelled to reject this theory of high tides, at least for 

 the interval which separates us from the beginning of the Laurentian 



