The next stratum (No. 5.) consists of grains of quartz, for the most part agglutinated into sandstone of different degrees of induration, and varying in colour from a light grey to a dark brown, whilst in some parts loose sand predominates. In the grey variety of this stone, marine shells of different kinds, are found in great abundance: in the brown they occur very seldom, and not at all in the sand. This stratum is considerably thicker than the two incumbent ones. Beneath this is the shale, {98} (No. 6.) which generally makes its appearance in vallies; but it no where exhibits a denudated termination. On sinking a shaft in the parish of Woodhall, about six miles south-west of Horncastle, it was found to be one hundred and fifty yards in thickness. A great variety of organic remains are also found in this stratum. Under the shale is a stratum of forest marble, which denudates about sixteen miles westward of Horncastle. The last division to be considered is an alluvial collection of earth, almost entirely consisting of the spoils of the neighbouring strata in a state of decomposition, wherein however detached pieces of the different strata are to be found unaltered. From this it appears that when these parts were deluged by the water, the current set in from east to west. As the chalk and the shale would present the largest surfaces to the erosion of the water, they would be more extensively acted upon than the other strata: hence the greatest part of the alluvial deposition consists of white marle and blue; the former (No. 7.) being of the least specific gravity, has covered the hills, while the latter with sand and gravel (No. 8.) occupies the lower parts. NATURAL HISTORY. In the department of Natural History, this district possesses but little which is deserving of particular notice. Of BIRDS there are none which can now be considered peculiar to this part, the drainage of the fen lands having entirely banished the great variety of aquatic birds which used, previous to that event, to be found here. The PLANTS, indigenous to this district, are very numerous. From a list of several hundreds which are to be found in the neighbourhood, the following interesting ones are selected.