T. Mellard Reach— Oscillations of Level of Land. 489 



after reaching a certain level and cuts out miniature river cliffs and 

 terraces and alluvial fans and bottoms. 1 Many other interesting 

 phenomena may be studied which I have no time to deal with here. 



The blown sand over its larger area rests upon peat which, 

 appearing on the shore at Alt Mouth, Lancashire, and Dove Point, 

 Cheshire, in turn rests upon Scrobicularia Clays (the Formby 

 and Leasowe Marine beds of my classification 2 ). I have found 

 Scrobicularia in situ in the erect position in which they lived in blue 

 clay immediately underlying the peat at both places. I also found, 

 by excavating through the peat at the Alt Mouth, a bed of cockles 

 and other common marine shells at a depth of seven feet. Sewer 

 excavations made under my directions at Birkdale and Hightown 

 proved the continuity of the peat under the sandhills and its 

 connection with the inland peat mosses. In the shore peat are the 

 stools of trees, which are, I am satisfied with most other observers, in 

 the position in which they grew. At the Alt Mouth they were very 

 plentiful twenty years ago, and even so far back as 1796 there is an 

 engraving in the Gentleman s Magazine, quite identifiable, exhibiting 

 " Eemains of a large Forest near Liverpool." Latterly the peat and 

 trees have been to a great extent swept away by the encroaching 

 tide. Oak was the most abundant, mixed with a great quantity 

 of birch and some Scotch firs. Elytra of beetles are to be found 

 in the peat and many bones of a small species of horse, antlers and 

 bones of the red deer, skull of a Bos longifrons, etc. Similar 

 mammalian remains are also found in the underlying blue clays 

 and silts. 



These clays and silts — the deposit getting siltier towards the 

 base — in turn rest upon an eroded surface of Boulder-clay, which 

 in cei'tain rare cases has another layer of peat (Lower Peat bed) 

 resting upon it. There is no doubt that the surface of the Boulder- 

 clay represents a land-surface with quite as much certainty as does 

 the Upper Peat, and one that is cut into channels by post-Glacial 

 streams and filled up by post-Glacial deposits. 



Underlying all these post-Glacial deposits come the Low-Level 

 Marine Boulder-clays and Sands of Lancashire and Cheshire, which 

 in turn repose ♦ upon the Trias, either the Bunter or the Keuper, 

 which may be well studied in quarries about Liverpool. The Low- 

 Level Marine Boulder-clays may be seen in the cliffs of Dawpool 

 on the Dee and in numerous brickworks about Liverpool. The 

 clay is usually of a brown or reddish-brown colour, and mechanical 

 analyses through sieves show various quantities of sand and gravel 

 mixed with clay and flour of rock. Many of the sand-grains are 

 most highly polished and rounded, as also is some of the fine gravel. 

 Mixed with the clay are the remains of numerous shells, of which 

 I have myself collected 44 species, many being of a Northern 

 facies. 3 The clay also contains Foraminifera, and in some places 



1 Science Gossip, 1881, pp. 198-206. 



2 "Post-Glacial Geology of Lancashire and Cheshire": Proceedings of the 

 Liverpool Geological Society, 1871-2. 



3 Q.J.G.S. 187*. 



