§ 29. In the eleventh century, the western bell-tower, the ground floor of which served as the main porch of the church, became common. The tower of the so-called 'Lincolnshire' type, with its stages separated by off-sets, and its double belfry window openings divided by a 'mid-wall' shaft, is found not infrequently in other parts of England, and survived, with some change in proportion and detail, for some time after the Norman Conquest. Some sixty western towers of the ordinary late Saxon type remain in England, exclusive of heightened porches, and of a few round towers in the eastern counties, where the absence of stone suitable for quoins made this shape desirable. It is probable that portions of many more exist beneath later additions. We have seen that in the tower at Branston, built more than a quarter of a century at earliest after the Conquest, the old type was retained--the slender tower, lofty in proportion to its area. The tower of Weaverthorpe in the east riding of Yorkshire, obviously Norman in its details, keeps the old proportions. Many towers, on the contrary, which, at first sight, might be associated with the Saxon group, shew Norman influence in the thickness of their walls and stoutness of their proportions. While the normal thickness of wall in the late Saxon towers of Lincolnshire is about three and a half feet, the thickness at Caistor is increased to nearly six feet. The normal area is from ten to twelve feet square: the area at Caistor is 15½ feet east to west by 17½ north to south. The normal width of the arch between tower and nave is about 5¾ feet: at Caistor it is nearly four feet more. At Tugby, between Leicester and Uppingham, there is a remarkable tower, built in a primitive fashion which shews distinct traces of Saxon kinship, but with proportions and with the introduction of detail which as clearly bear witness to its post-Conquest date. Hooton Pagnell, near Doncaster, has a large western tower which follows the Saxon tradition of the simple rubble tower with small stone quoins and without buttresses; but the character of the arch leading into the nave is distinctly Norman, and the tower is not merely of unusually large area, but is the full breadth of the spacious nave beyond it. While the western tower increases in area, it does not at first acquire buttresses at the angles: these, in their flat pilaster-like form, begin to appear in the course of the twelfth century. [Illustration: Fig. 7. Carlton-in-Lindrick, Notts.: west tower, of late Saxon type, with later additions.]