The lesser windows of the towers are usually small and narrow, with an inner splay. Their outer openings are often flanked by very large dressed stones: their rounded heads are seldom arched—there is a good arched window head in the south wall of the tower at Coleby—but are more often cut in the under side of a lintel; and sometimes this cut, exceeding a semicircle, produces the “key-hole” form of opening. At Rothwell there is in each wall of the tower, below the “mid-wall” windows, a small rectangular opening with a wide inner splay: a somewhat similar opening pierces the wall above the west door at Nettleton. In the masonry of these towers two striking features are apparent. One is the disappearance of that “through-stone” treatment of dressed masonry, which is an undoubted characteristic of early Saxon work. A little doorway in the west wall of the north transept at Stow has voussoirs and jamb-stones, each of which faces the whole thickness of the wall. But the jambs below the tower arches are faced with double or triple, not single stones. And while it is rare to find a tower arch or doorway of this style formed of a core of rubble between facings of dressed stone, yet there are few in which the facing stones do not become less closely set together, and wide rubble fillings do not take the place of neat and close jointing. The other feature is the appearance of “herring-bone” masonry. This may be seen in some profusion at Broughton, and in a striking and unusual form at Marton; and, although it is not general, it occurs in other places. Modifications in the tower plan are almost confined to an increase of dimensions which, in some members of the group—notably Caistor—is rather remarkable. One tower alone—Great Hale—introduces a newel staircase into an angle of the fabric; and this is almost absurdly unsuited to the probable size of those who had to climb it. We have seen that, at Hough and Broughton, nearly circular excrescences were formed to hold stairs on the west side of the towers. As a rule, we may believe that the upper floors of the towers were approached by ladders. It may be noted that in Lincolnshire there are very few of those openings above the tower arch, which are often quoted to prove the use of the tower as a place of habitation, and probably led to a landing and wooden stair communicating with the interior of the church. There are such, as at St. Peter-at-Gowts, Winterton, and Broughton; but they are exceptional, and the probable plan of Broughton makes it possible that, as at Barton-on-Humber, the opening was merely a piercing in the wall between nave and chancel.