DIAGRAM ILLUSTRATING THE THICKNESSES OF THE IRISH MESOZOIC AND CAINOZOIC ROCKS, 



ALSO THE SUPERFICIAL ACCUMULATIONS. 



Proc. R.D.S.V0I. IIl.N.S. 



Plate "71 1 1 



. „n nkce do all the Superficial Accumulations occur together. 

 „'"i lanvof the different Drifts exceed 100 feet in thickness, 

 ''T ^ illv rael is rauch les.. I'he Alluvium in some of the ancient 

 ""tSdeS.™ considerate thickness. The Peat in some of 

 f^ , i Lml 01 •• Red Bog" is of considerable thickness. The Lough 

 xwhberae bJst developed nea, Lough Neagh, but they have 

 ftls° ten found in the Co. Tipperary; they consist of plastic clays 

 and sands with scams of Lignyte. 



•I'll!' I'niiilivc SericM are nearly solely bedded Dolerytes and 'luffs. 

 In nlncfs tlicre is a zone of Iron Ore Measures, from 1 to fiO feet in 

 tlilckiu'ss at a height of about 800 feet, while in other places there 

 is a zoii J about 250 f( et lower. Lignyte occurs in places. The 

 Ihisal .Scries Is more usually a conglomerate, but in places it is a 

 limestone. It often cniitaiiis plant remains in shaly lieds, or even 

 licds of Lignyte or Iron ore. 



These lincks have suffered considerably from denudation. In no 

 place Is the full thicknossi found, because where the Greensand is 

 bust develiiped.tlie White Limestone has been considerably denuded. 



This sinidl ihii'kiicss (;f Lias is considered by Tate to represent the 

 ZiUK's nf Ik'lcniiiili-s lu utus, Ammonites Bucklandi, A. angulatus, 

 A. plaiuirliis, anil a lou'cr Zone. 



The lihoetlc Beds are thickest atLnrnc, Co. Antrim. 



The Ti'ias^ic Beds seem to be best developed in S,E. Antrim, 

 adjoiiiinn' lielfiist Lougli. Near Carrickfergus, they contain a con- 

 siaoralilcihidiucMSdf Suit measures, wliile near Coagh, Co. Tyrone, 

 and ni'ai' Kiiisscomt. Co. Cavan, deposits of Gypsum have been found 

 In thuiii. Near Ardtrea, Tyrone, and at Scrubo Hill, Co. Down, there 

 seem to lie Inicrbedded Dolerytes. 



Vi'ry little Is km 



ivn about the Permian; it is very imperfectly 



iNposoil at Oultia.ou Belfast Lough : in the Co. Tyrone, and perhaps 

 ui the Lag»ii Valley. 



Superficial 

 Accumulations. 



iEolian Drift. 



Alluvial Deposits. 



Peat (Bog.) 



Esker and other Marine Drifts. 



Olacialoid Drift (Meteoric.) 



Moraine Drift 

 Boulder-clay do. 



Glacial. 



Lough Neagh Beds. 



BREAK 



Miocene. 



Iron-ore Measures. 



Eruptive Series 

 1,200 feet. 



(Basal Series 

 I '.'0 feet. 



BREAK 



Cretaceous <^ 



1^0 



/Jurassic jfl: 



BREAK 



Pentiian J^ 



OTiite Limestone (Indurated Chalk 200 feet. 

 Hibernian Greensand, 100 feet, 



Lias. 



Rhtrtic 100 feet. 



> Keuper LlOOfcet 



Salt Measures 

 100 feet. 



Burner, aoO feet. 



Interbetliled Doleo'c 

 Ardtrea, Co. Tyrone; and 

 Scrabo lliil,Co. Down. 



BREAK 



Palaeozoic Rocks. 



SeaUS333/itt 10 On* Inch. 



