HA RD WICKE'S SCIENCE- G OS SI P. 



51 



the little progress which has been made in this branch 

 of labour during the centuries that have gone into the 

 historic past. 



If we leave Haltwhistle on a bright, crisp morning, 

 full of vigour and ready for an exciting tramp, a very 

 pleasant day lies before us. After a brief glance at 

 the town — which is not so interesting as some others 

 in the neighbourhood, either historically or artistically 

 — we strike away to the north-west, and after a brisk 

 walk, come to valleys, ravines, streams, quarries, and 

 mines of exceptional attractiveness for the student of 

 natural history. In the streams and pools, the fresh- 

 water plants and shells abound, and not a few are far 

 from common. While every bank, nook, and cranny 

 is bedecked with moss, and lichen, and fern, the 

 quarries present many features of interest. Coal, 

 clay, sandstone, are all in close proximity, and each 

 invites our attention. Worm-tracks, striking ripple- 

 marks and rain-drops abound in the latter, which 

 varies greatly in texture and colour, and often 

 contains a good deal of mica and other minerals. 

 The streams too, especially where unpolluted by 

 mining operations, prove attractive to geologist as 

 well as botanist, for they have many a story to tell of 

 obstacles presented to their course, and conquests won 

 over boulders of many kinds, which now repose in the 

 rugged water-course like subdued and vanquished 

 heroes. 



Such wayside studies as these beguile the time 

 and make it pass all too quickly, and we find by our 

 watches that it is necessary to hasten on. We there- 

 fore strike for a farm-house and hamlet known as 

 Wall-town, and having reached the heights to the 

 north, find ourselves on the very ridge along which 

 the wall was constructed. Like the Great Wall of 

 China, this lesser structure ran up and down, in and 

 out, following the course of stream and cliff which 

 aided the work of defence. Here we find ourselves 

 actually on the wall itself, and now for miles in either 

 direction we can trace its rise and fall (in more senses 

 than one), and study many points in connection with 

 its history. We soon observe that the line of hills 

 which run along from west to east are of an eruptive 

 formation, the rocks standing out here and there in 

 such a way that when a small portion is dislodged 

 with the geological hammer, its green tint and 

 volcanic origin may be seen at a glance. This is the 

 stone, here always known as "whinstone," when 171 

 sitti ; " cobbles," when found in river bed or amongst 

 gravel, and generally known as "basalt" elsewhere. 

 This is the stone which the Roman workmen quarried 

 with such patience and skill for the construction of 

 the wall throughout this part of the district. Here 

 and there we find sandstone blocks intermingled, and 

 the rubble which fills up the middle portion is 

 perhaps as often of sandstone as of basaltic origin, 

 but, as a whole, thousands upon thousands of whin- 

 stone blocks, all square-cut and beautifully laid, 

 form the northern and principal face of this historic 



pile. We take the westerly direction for convenience, 

 and because there are two special points of interest to 

 study, and wend our way along the top of the wall, 

 or by its side, now admiring the pretty patches of 

 Lecidea covering the more exposed rocks and stones 

 of l)asalt, now culling a pretty fern or fruiting moss, 

 and anon fishing out a banded Helix or other thing 

 of beauty, till at last we alight on one of the stone 

 turrets or watch towers, which stood about three 

 hundred yards apart, and thus enabled the sentinel 

 to keep up communication all along the wall. These 

 towers are twelve feet square, and as several of them 

 have been cleaned out, they have told their own 

 story of the past. At Greenhead we shall have an 

 opportunity of seeing one of these in the process of 

 being opened, but let us first step aside for a moment 

 to ascertain whence comes the chink, chink, which we 

 hear. Yonder, some hundred feet below us there are 

 workmen busy with pick, and shovel, and hammer. 

 They are quarrying whinstone, and the ridge along 

 which we are walking is gradually receding before 

 them. We look at the top of the works, and are 

 amazed at the way in which the basalt has been 

 weathered, then carefully descend into the workings 

 beneath. What a splendid sight ! That bold face 

 of bluish-green rock has a wonderful tale to tell. It 

 was once a super-heated mass which could not 

 contain itself within the narrow bounds imposed by 

 cold, unbending rocks, and with one mighty effort 

 tore asunder the chains which bound it and poured 

 out its fury on the quivering earth-crust to cool in 

 due course and set into this solid mass ! Here, 

 guided by an intelligent Welsh quarryman, we see 

 the very sandstone over ! which the lava flowed, 

 and it is curious to observe how both the sandstone 

 and basalt have been affected by the action. The 

 stone quarried here varies in texture at different 

 heights, from which we infer that the coarser, denser 

 particles by their specific gravity subsided to the 

 bottom while the mass was still mobile and liquid, 

 the finer particles floating nearest the surface. We 

 have never visited a quarry which produced upon us 

 a profounder impression than this one has done. 

 And now for a run to Carvoran which is nigh at 

 hand, and we shall see the quarter-miie turret which 

 has just been opened. It stands off the main road — 

 the Maiden Way, perhaps, of the Romans — and is near 

 a farm-house. Among the " finds " there are sundry 

 pieces of pottery, some iron articles, bones of different 

 kinds, the jaw of a carnivorous brute, whose teeth 

 have been greatly worn down by the constant 

 crushing of bones, and sundry pieces of horn which 

 have evidently been employed in various ways. We 

 are now within a short distance of Greenhead Station, 

 whence we can take train to Carlisle or Newcastle or 

 if we prefer, can run on to the pretty resort at 

 Gilsland and after a night's rest, a drink at the Spa, 

 and sundry pilgrimages, find our way to Birdoswald 

 where one of the most complete stations on the 



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