But this bare valley, botanically regarded, is a bit of the far North, interpolated between Durham, Westmorland, and Yorkshire, where the Teesdale basalt or "whinstone" affords an advanced station for many rare plants of the highland type as they trend southward; and there, for five or six miles, from the upper waterfall of Caldron Snout to that of High Force, the banks of the Tees, with the rough pastures, scars, and fells that form its border, hold many floral treasures. The first flower to attract attention on these wild lawns is that queen of violets, the mountain pansy (_viola lutea_), not uncommon on many midland and northern heaths, but nowhere else growing in such prodigality as here, or with such rich mingling of colours--orange yellow, creamy white, deep purple, and velvet black--till the eye of the traveller is sated with the gorgeous tints. To the violet tribe this pansy stands in somewhat the same relation as does the bird's-eye primrose to the _primulas_; it is a mountain cousin, at once hardier and more beautiful than its kinsfolk of wood and plain. Seeing it in such abundance, we can understand why Teesdale has been described as "the gardener's paradise;" but the expression is not a fitting one, for "gardener" suggests "trowel," and the nurseryman is the sort of Peri to whom the gates of this paradise ought to be for ever closed. But perhaps the first stroll which a visitor to Upper Teesdale is likely to take, is by the bank of the river just above High Force; and here the most conspicuous plant is a big cinquefoil, the _potentilla fruticosa_, a shrub about three feet in height, bearing large yellow flowers. Rare elsewhere, it is in exuberance beside the Tees; and I remember the amused surprise with which a dalesman regarded me, when he saw my interest in a weed that to him was so familiar and so cheap. But the smaller notabilities of the district have to be personally searched for; they do not obtrude themselves on the wayfarer's glance. On the Yorkshire side of the stream stands Cronkley Scar, a buttress of the high moor known as Mickle Fell; and here, in the wet gullies, may be found such choice northern plants as the Alpine meadow-rue; the Scottish asphodel (_Tofieldia_), a small relative of the common bog-asphodel; and the curious viviparous bistort, another highland immigrant, bearing a spike of dull white flowers and small bulbs below.