1 91 1- Revieivs* 53 



AGRICULTURAL GEOLOGY. 



The Geological Features and Soils of the Agricultural Station of the 

 Department of Agriculture at Ballyhaise in the County of Cavan. 



By J. R. Kii.ROE, A.R.C.Sc.l. ; H. J. Seymour, B.A., F.G.S. ; 

 aiul T. Hallissv, B.A. Pp. 50 (with coloured map). Dublin : H. M. 

 Stationery Office, 19IU. Price, is. fxl. 



This memoir published by the Department of Agriculture is not so 

 much a new departure as a following up of the line pursued in the memoirs 

 of the Dubhn, Belfast, Cork, Limerick and Londonderry districts, where 

 the soils commamled a degree of consideration. 



Chapter I. is occupied with a description of the general features of 

 the station. The farm of 874 acres, has 653 acres arable, 147 occupied 

 by woods, and 44 by peat, whilst the remaining 30 are covered by the river 

 Annalee, Avhich passes through them in a meandering course. This river 

 supplies power for driving mills and dairy machinery at a point cast of 

 Ballyhaise House. In Chapter IL Mr. Kilroe deals with the solid geology. 

 T'wo formations, the Ordovician, consisting of fine-grained sandstones, and 

 the Carboniferous, which occurs il miles N.E. of the village of Ballyhaise, 

 are discussed. 



Professor Seymour gives a very interesting chapter on surfacc-dejwsits, 

 and deals with the question of the origin of drumlins, those curious 

 elongated mounds which can hardly have been produced by any process 

 of weathering with which we are familiar. He states that "it is fairly 

 certain that the shape of the drumlins is original and is connected with 

 the movement of the ice -sheet at the time of its maximum development. 

 The probability is that a certain condition of the rock-floor such as the 

 presence of hummocks obstructing the sole of the glaciers, has had 

 something to do with the phenomenon, for many of the more typical 

 drumlins have a rock-core masked beneath a mantle of boulder-clay. 

 Their formation would appear also to be connected with divergent 

 movements of the ice -sheet locally, such divergence being primarily due 

 to the presence of rock-obstructions which led to the accumulation of 

 boulder-clay in certain places. The continued movement of the ice-sheet 

 caused it ultimately to over-ride the mass and give it its present 

 characteristic shape." Plates I. and III. give a good idea of the shape 

 of these drumlins, while the other, Plate II., shows a strong contrast 

 between the vegetation on the drift and the coarser kind on the bare 

 ground. It is interesting to note how the alluvial deposits arrange 

 themselves into two distinct types — a loam forming a bank, in one place 

 six feet high, by the sides of the stream, while the less heavy mud was 

 carried further over the flooded meadows. 



Mr. Kilroe, in Chapter IV., gives an account of the origin of the soils, 

 and in Chapter V. discusses the properties of these that most affect 

 agriculture. Water capacity or " minimum water capacity," i.e., that left 

 in a soil which is properly drained, as a film, is found to depend upon 

 size of soil particles, increasing with their minuteness. The amount of 

 the fine material governs percolation, for though the percentage of gravel 

 may be great, yet this finest material may act as a clay and impede both 

 percolation and also the passage of air. 



