114 O. S. Kinahan — Re-arranged Glacial Drift. 



fragments, these being more frequent where it approaches the true 

 glacial drift than elsewhere, while ice-dressed blocks are also some- 

 times found in the marl or clay ; and, what appears to be remarkable, 

 many of the blocks in these argillaceous accumulations may retain a 

 good polish, while the polish on the block in the Glacialoid drift is 

 more or less obliterated, as if by the attrition of sand, etc. 



The Glacialoid drift usually contains fragments of fossils, chalk, 

 and flints, and shows other features characteristic of the typical shelly 

 drift, often in lenticular patches of gravel ; and, except in the imme- 

 diate proximity to the true glacial drift, lenticular patches, layers, 

 and partings of gravel, sand, marl, or clay, occur more or less 

 frequently, the mass being more or less distinctly stratified. This 

 drift is always at about the same elevation as the shelly drifts into 

 , which it graduates. A peculiarity of the contained blocks and 

 fragments is, that in some places they all, in other places the 

 majority of them, stand on edge, which seems seldom to be the case 

 in typical Boulder-clay drift and rarely in Moraine drift.^ 



The accumulations formed during the time of the 100 feet beach, 

 near the east and south-east coasts, are similar in materials to those 

 of the first, and may be shingle, gravel, sand, clay, or marl. They 

 always contain fragments of fossils, but many of these evidently belong 

 to the older gravels, etc., from which the newer drifts were formed. 

 They are found in some of the valleys running inland, and seem to be 

 more or less regularly distributed at heights under 100 feet. On the 

 west coast, fossils have not been recorded in them ; but these de- 

 posits, sometimes forming cliffs or shelves in the hill-sides, have been 

 noted in places in the counties Cork, Kerry, Clare, Galway, and 

 Mayo. Their limits and altitude, however, are very uncertain, on 

 account of the gravels, etc., of which they are formed being similar 

 to those of the " Esker-sea period." In the vicinity of Menlough, 

 N.N.E. of the town of Galway, there is a "remarkable sea-beach-like 

 bank." This in one locality is a well defined shingle beach, at an 

 altitude of about 80 or 90 feet ; but toward the N. W. and N.E. it 

 seems to graduate into gravels, those to the N.W. being traceable 

 onwards up to a height of 150 feet. In most of the low valleys in 

 West Galway there are well developed tidal bars between the 100 

 and 120 feet contour lines. These probably mark the margin of the 

 same sea-level as those at Menlough, but are at a higher level on 

 account of the great Post-Glacial faults that traverse the valleys now 

 occupied by Lough Corrib and its tributaries. 



The third time, one of rest, is recorded by the raised beaches of 

 shelly sand and gravel found in different places close to the coast- 

 line, but especially near the north-east and south-west coasts. These 

 were also observed on one of the Aran Islands, Galway Bay. In other 

 parts of Galway, also in Mayo, there are terraces of gravel that appear 

 to have been formed at this time ; while in places in the co. Clare 



^ In typical Boulder-clay drift there may be subordinate portions in -which the 

 blocks stand on edge. This, however, seems always to occur in places where we may 

 suppose an iceberg or shore-ice was aground on the Boulder-clay drift, and shoved 

 the blocks up on end. 



