268 Proceedings of the Royal Irish Academy. 



the aberrant deflection of the contours in this direction, as shown on the one- 

 incli contoiired map of this hill, and by the small map above (fig. 2, p. 267). 



Similar features were observed in a great number of areas during the 

 progress of this investigation, and have proved of great service in the 

 determination of the direction of ice-flow, when other means have failed or 

 been indecisive. They suggest the possession by ice of great power to mould 

 any drift deposits over which it passes, and thereby render very improbable 

 the preservation of drift features, such as the supposed drumlins just referred 

 to, which are inconsistent in direction with its movement. 



The surface of the country stretching east of Slieve Beagh is character- 

 ized by extreme irregularity, due partly to moraines, partly to drumlias.^ 

 The latter features trend roughly south. Numerous lakes, lakelets and 

 marshes lie between the mounds and ridges, while the Eiver Blackwater 

 winds in and out among them. Commencing a few miles south-west of 

 Castlecaulfield and extending via Douaghmore to Cookstown, there occurs a 

 huge morainic belt, in places three and more miles wide, which was formed 

 as a great recessional moraine of the Donegal ice-sheet. This must still have 

 been of considerable thickness, as the belt nowhere shows a lobate arrange- 

 ment coiTCsponding witli its large constituent glaciers issuing from the west. 

 The moraine is perhaps best seen at Donaghmore and to the X.-X.-E. of this 

 village, where it forms a wide strip of country studded with kettle holes and 

 exhibiting the characteristic billowy surface. Its vegetation, moreover, is 

 equally decisive as to its character, the zerophytic grasses of these sand and 

 gravel tracts contrasting most forcibly with the siuTounding growth.^ Tliis 

 moraine spreads south-eastward to Dungannon, which, like Cookstown, is 

 largely built upon its surface. The Castlecaulfield and Auglmacloy country 

 is likewise clearly morainic, the drainage hereabouts being peculiarly T-shaped, 

 chiefly due to the crossing of the drumlin and morainic directions. 



This great morainic belt represents an earlier period of halt than the 

 Pomeroy and Tyrone moraines, and was formed prior to the break-up of the 

 ice-sheet into the lobes of the glaciers feeding it. It does not, however, 

 represent the terminal moraine of the Donegal ice formed at the maximum 

 extension, for the latter was continuous with the Scottish sheet, and pro- 

 ceeded much fui-ther eastward. The evidence for this is furnished by tlie 

 features and by the composition of the drifc in the country to the east and 

 south-east. Furthermore, it seems necessary on a priori grounds to suppose 



1 Tlie one-inct coutoared uiap of the O.S. gives some idea of the complexity aud 

 intricacy of these features. 



- On this gravel belt, as on other large moraines, are situated the great demesnes of 

 the area, e.g., Parkauaur, Donaghmore Ho., Desertcrest Ho., Loughry Ho. and 

 Killymoon Castle. 



