Similar formations are found in the Mediterranean, where a dark mud predominates in the western part, passing into a grey, marly slime in the Tyrrhenian Basin and replaced by a typical calcareous ooze in the Eastern Basin.
On the East Shore to the north is a marly loam overlying a yellowish-red clay sub-soil, to the south is a soil quite stiff with light coloured clay, while here and there, especially in the middle and south, are considerable areas both of light sandy soils and tidal marsh loams. On the West Shore the soils range from a light sandy loam in the lower levels south from Baltimore to rather heavy loarns overlying a yellowish clay on the rolling uplands and on the terraces along the Potomac and Patuxent.
He obtained a considerable addition to his resources (Carlyle puts the amount at £10,000) on his marriage in 1767 to Betty Anne, sole child and heiress of John Dawson of Marly in Yorkshire.
The northern portion is generally level; the soil is of indifferent quality, strong and marly in a few places, but rocky in all the valleys of the Sierra de Avila; and the climate alternates from severe cold in winter to extreme heat in summer.
He was not permitted, however, to complete the work, being compelled to yield to the king's preference for residences outside Paris, and to devote himself to Marly and Versailles.