516 Geological Society: Mr. Lyell on the Fossil 



ham of Liverpool*, but he is now convinced of the justness of the 

 inference, having observed similar markings produced on very soft 

 mud by rain at Brooklyn in Long Island (New York). On the 

 same mud were the foot-prints of fowls, some of which had been made 

 before the rain and some after it. 



Mr. Lyell next visited the red and green shales of Cabotville, north 

 of Springfield in Massachusetts, where some of the best Ornithich- 

 nites have been procured, chiefly in the green shale. The clip of the 

 beds is 20° to the east, a higher inclination, the author says, than 

 could have belonged to a sea-beach. He observed in the same quar- 

 ries ripple-marks as well as casts of cracks, and he was informed 

 that the impressions of rain. drops have likewise been found. 



In company with Prof. Hitchcock, Mr. Lyell afterwards examined 

 a natural section near Smith's Ferry, on the right bank of the Con- 

 necticut, about eleven miles north of Springfield. The rock con- 

 sists of thin-bedded sandstone with red-coloured shale. Some of the 

 flags are distinctly ripple-marked, and the dip of the layers on which 

 the Ornithichnites are imprinted, in great abundance, varies from 

 eleven to fifteen degrees. Many superimposed beds must have been 

 successively trodden upon, as different sets of tracks are traced 

 through a thickness of sandstone exceeding ten feet ; and Prof. 

 Hitchcock pointed out to the author that some of the beds exposed 

 several yards farther down the river, and containing Ornithichnites, 

 would, if prolonged, pass under those of the principal locality, and 

 make the entire thickness throughout which the impressions prevail, 

 at intervals, perhaps twenty or thirty feet. Mr. Lyell, therefore, con- 

 ceives that a continued subsidence of the ground took place during 

 the deposition of the layers on which the birds walked. 



It has been suggested, but the opinion has not been adopted by 

 Prof. Hitchcock, that the eastward slope of the beds represents that 

 of the original beach. With a view to this question, Mr. Lyell exa- 

 mined the direction of the ripple-marks, and found that it agreed with 

 the dip, or was at right angles to the supposed line of beach ; but he 

 adds, though this agreement presents a formidable objection to the 

 suggestion above alluded to, if the ripples were produced by waves, 

 yet it does not disprove the opinion, as the ripples do not exceed in 

 dimensions those which are produced by sand blown over a muddy 

 beach, and often distributed at right angles to the coast-line. In- 

 stances of this effect of the wind Mr. Lyell has remarked along the 

 shores of Massachusetts. Nevertheless he is of opinion that the 

 rippled layer of sandstone in question contains too much clay to have 

 resulted from blown sand, and he is disposed to think that in most 

 of these localities the strata have been tilted, instances of such dis- 

 turbance having been pointed out to him by Prof. Hitchcock in the 

 state of Massachusetts, and by Mr. Percival near Newhaven in Con- 

 necticut. In reference to this subject, he says, that a few miles from 

 Smith's Ferry a conglomerate, several hundred feet thick, containing 

 angular and rounded fragments of trap and red sandstone, the base 

 being sometimes a vesicular trap and trap tuff, passes upwards into 



* See Phil. Mag. S. 3. vol. xiv. p. 507. 



