168 G. H. Kinahan — Re-arranged Glacial Drift. 



as plentiful in the true Coal Measures as in tlie Lower Lias. I am 

 not aware whether these so-called teeth of Cladodiis, which I have 

 shown to be Hyhodus, have ever been found in the Subcarboniferous 

 Limestone, but I know that the teeth of true Cladodi have been 

 found in that series of strata. The teeth of both Hyhodus and 

 Cladodus from these Measures have been obtained in close proximity 

 to, and even buried in, masses of shagreen and cartilage, and also 

 associated with the spines and tubercles of Ctenacanihus and Gyra- 

 canthus. I hope in another paper to show from specimens in my 

 possession that Ctenacanthiis pertains in all probability to the same 

 fish as the teeth of Hyhodus, and that it therefore does not belong to 

 a separate genus called Ctenacanihus, but to a variety of Hyhodus. 



V. — Glacialoid or Ee-arranged Glacial Drift. 



By G. H. Kinahan, M.R.I.A. 



[Concluded from page 117.) 



Let us now consider the recent drifts that in other places are 

 being formed at the present day. In portions of the sea-coast of 

 Western Ireland, but especially in Galway and Mayo, there are cliffs 

 of glacial drift margining the Atlantic. These are degrading away 

 yearly, the detritus being carried away to form submarine and 

 estuarine deposits. Generally, on the open seaboard, these materials, 

 prior to being re-deposited, are so tossed about that they retain no 

 indication of their former origin ; but this is not the case everywhere, 

 for in the bays and archipelagos they are in places very little 

 changed, and different varieties of drift are being deposited, namely, 

 fine silt or mud, sand and gravel, and a nearly unchanged or 

 Glacialoid drift, the latter consisting of all or most of the materials 



Diagrammatic Section, showing the relations between an ancient cliif of glacial drift 

 and the rearranged or Glacialoid drift with the associated shelly drifts. 



A, D, B, present surface of the ground, due to meteoric denudation. 



C, D, E, ancient cliff of glacial drift. 



a. Glacialoid drift, due to meteoric weathering. 



h. Sand, gravel, clay and marl. 



c. Glacialoid drift, due to sea action comhined with landslips and other meteoric action. 



