in relief (Fig. 4). The oblong slabs are always upright, and ornamented on both sides, not recumbent like the Irish slabs. They generally bear on the obverse a cross of the Celtic form occupying the full size of the stone. This form of cross has the four angles at the junction of the arms with the upright shaft hollowed out with a circular or square recess, and the junction surrounded with a circular band. The oblong form of the slab is preserved entire, and the portions of the surface on each side of the cross are usually covered with sculptures representing symbols or interlaced patterns arranged in panels (Fig. 5). The cross itself and the other figures are carved with elaborate designs of interlaced work, or with frets or divergent spirals. The reverse of the slabs is also covered with sculpture representing symbols and conventional or symbolic figures (Fig. 6). The sculpture on these stones bears a close resemblance to the designs of the Celtic MSS., so close, indeed, that each sculptured monument might be a page of MS. carved in stone. This indicates, as pointed out by Dr. J. Anderson, that the designs were first wrought out and brought to perfection on the pages of the MSS., and reproduced at a subsequent [Illustration: FIG. 4.--Cross at St. Madoe’s, Perthshire.] period on the stone monuments. The earliest Celtic MSS. date from the end of the seventh century, while the decorated slabs are probably of the ninth to the twelfth centuries.[37] A distinct change or progressive development is observable in the forms of the sculptures and ornaments of the above monuments. The Celtic design gradually gives place to new features which bring it into conformity with the decorations of the MSS. and metal work and the general progress of the country. It thus at length becomes merged in the general design of the twelfth century, as introduced from the South along with the other effects of the Roman influence. The interlaced work, spirlets, and fret work give place in course of time to scrolls and leaf ornaments (Fig. 7). The crosses, formerly enriched with divergent spirals, become carved with leaf or flower patterns, the peculiar Pictish symbols disappear, and the Celtic cross gives place to the more ordinary Norman form. Upright cross slabs are abandoned and recumbent slabs take their place.