38 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Many of the beds of rock are more or less ripple-marked, but it is 

 on two or three of the lower beds only that any of the foot-tracks have 

 been found. The line of the stratification is vei*y even and uniform, 

 with a southerly dip of one in twelve. The foot-tracks are generally 

 either up or down the slope, although, at times, the track is in a dia- 

 gonal direction ; some are faint, whilst others are more deeply in- 

 dented. The ripple-marks present every variety of form that may 

 at present be met with on a modern sandy beach. There is the con- 

 tinuous, nearly straight, and nearly parallel ridge ; there is the short, 

 dappled, pitted condition ; and there is also the smooth surface. The 

 directions of the ripple-marks are not all one way in the various beds 

 overlying each other ; but they have been changed in their direction, 

 probably with a change of current or of wind. In a thickness of less 

 than an inch there may be seen two sets of ripple-markings at right 

 angles to each other, plainly showing a corresponding difference in 

 the causes which produced them. 



Where the foot-prints are preserved, there is always, in the divi- 

 sions of the beds of rock, a bed of clay, varying from one to twelve 

 inches in thickness. Some of the thicker beds of clay also exhibit 

 sun-cracks. The clay has evidently been held in suspension by the 

 tidal waters, and has been deposited over the sandy beach betwixt 

 high and low water ; the animals have walked over the yielding shore, 

 to and from the water, leaving the prints of their feet on the clay, 

 and the sun has dried the freshly-formed mud. With the beach in 

 such a state as described, the next deposit has been sand, which, 

 either held in suspension in water, or drifted by the wind, has been 

 quietly deposited over the impressions, and the next and succeeding 

 tides brought sand, and laid it out over the beach, until the next local 

 change again caused a deposit of clay or mud ; thus dividing the 

 beds of rock into strata of various thicknesses, as now exhibited in 

 the quarries. 



There are several ways to account for this alternation in the stra- 

 tification. The ancient beach we are contemplating may have 

 bounded a tidal river, or an estuary, or the ocean ; but most proba- 

 bly an estuary having clay or marl strata within the reach of spring- 

 tides, floods, or storms, and extensive sand-banks within its waters. 

 Violent action would saturate the waters with mud, as land-floods 

 and spring-tides in the River Mersey are now saturated ; whilst a 

 calm and steady current over sand-banks would carry only the finer 

 and lighter portions of the suspended material which would be de- 

 posited over the beach. Thus like causes would produce like effects, 

 and the ocean of that distant date doubtlessly rolled as freely, and 

 the sun shone as brightly and warmly as now. Of this we are cer- 

 tain, that there were earth, water, air^ and heat ; and that there also 

 were animals, apparently of strange and uncouth forms. Traces of 

 vegetables in these deposits are not common, and such as are found 

 are generally detached fragments lying horizontally, the hollow stems 

 filled with the material of the surrounding rock ; the sohd portions 

 of the plants are carbonized, and the whole are compressed in the line 



