The Highland Boundary Fault : Reverse or Wrench Fault?
DETAILED work which I have done in the Loch Lomond area suggests a definite answer to the above problem which is of some importance since it concerns one of the major geological features of the British Isles. The direction in which the principal stress acted in the production of the fault can be approximately determined from the pattern of structures in the Lower Old Red Sandstone conglomerates, and this supports the contention put forward in stratigraphical accounts (summarized by J. G. C. Anderson1) that the Highland Boundary Fault is a reverse fault of Caledonian age and not a Proto-Armorican wrench fault as envisaged by E. M. Anderson2.
The Lower Old Red Sandstone rocks of the Balmaha-Aberfoyle region
The object of this paper is to describe the Lower Old Red Sandstone Rocks, as they occur along the Great Highland Fault, and to elucidate, where possible, their relationship to the peculiar jaspery and serpentinous belts to be found in this region.

The vast masses of coarse conglomerate which are so well known all along the Great Fault, in Perthshire and farther north-east, are just as well developed in the region between Callander and Loch Lomond, and, through their relatively great resistance to weathering, form prominent ridges and hills.

Thus we have the Menteith Hills and the chain of ridges between Aberfoyle and Balmaha—Arndrum, Drum of Clashmore, Gualann Hill, and Conic Hill; while away to the S.E. the softer sandstones form an undulating tract of lower ground: for example, Flanders Moss, Buchylvie, Balfron and Drymen.

The Great Highland Fault can be traced from the S. shore of Loch Vennachar (at Invertrossachs) along the N.W. face of the Menteith Hills, and cutting through the eastern portion of the Clachan of Aberfoyle. Its outcrop is then obscured by alluvium for some considerable distance, but it passes almost along the bed of the Bofrishlie Burn (on the N.W. face of Arndrum), and along the Boninty Burn.

Near Drum of Clashmore the fault appears to branch, giving rise to two faults, which continue for several miles, with a comparatively small distance separating them from one another.

The more north-westerly fault is now everywhere in contact with supposed Ordovician grits and hornblende schist, and is
An operational method for estimating signal to noise ratios from data acquired with imaging spectrometers
A method, using the concept of local means and local standard deviations of small imaging blocks and using a box counting procedure, has been developed for unsupervised estimation of the average signal to noise ratios of images in which the noise is additive. The method has been applied to simulated images with Gaussian noise, to images acquired with the Airborne Visible Infrared Imaging Spectrometer and with the Geophysical and Environmental Research Imaging Spectrometer. The method is compared with other techniques for estimating signal to noise ratios from imaging data. It is believed that the method is generally applicable to images having many small homogeneous blocks. Because the method does not take into account interband effects, it is not appropriate to use the method to estimate signal to noise ratios from images having nonnegligible interband radiometric calibration errors at spatial scales less than or equal to the size of the small imaging blocks used in the noise estimation.