59 



Tlu 1 excavation was carried below the line of permanenl saturation, 

 and foundation piles driven from eight to sixteen feel before reaching a 

 firm substratum. The piles were sawed off about fifteen inches above 

 the bottom of the excavation and the spaces between, and for one fool 

 outside of them, was tilled with cement concrete and well rammed. 

 Longitudinal timbers twelve 1 inches square were placed on the tops of 

 the piles and were secured to them hy iron holts seven-eighths of an 

 inch square, and seventeen inches long. Upon these, at right angles to 

 them, were placed other timbers of the same si/.e, which were notched 

 down so as to interlock with those first laid. These timbers were all 

 completely imbedded in cement concrete. Upon these timbers, planks 

 six inches thick were laid so as to leave alternate spaces equal in width 

 to the plank. These spaces were tilled with concrete. 



The timber work is all placed at such depth as to ensure its dura- 

 bility ; being below the line of permanent saturation. 



Upon this sub-structure the large stones of the foundation masonry 

 were laid. The balance of the foundation to within one foot of the 

 grade of the walk is constructed with large blocks of gneiss rock laid 

 in cement. 



The face stones above the walk to the springing line of the arch are 

 of Hudson River "mountain graywacke." Work was suspended at 

 this point for the season. 



The archway in the east wood is designed to carry a carriage and 

 bridle road over a walk. 



The facings are of Ohio and Belleville sand stone alternating, and the 

 interior arch is of common hard brick. This is to be lined with panel 

 work in wood. 



In excavating for the foundation of this archway a coarse compact 

 gravel was found, and the excavation was carried only three feet below 

 the grade of the walk. A layer of concrete one foot in thickness was 

 laid, and upon this the masonry commenced. The masonry of this 

 structure was completed late in the season. The wood work is not yet 

 complete. 



To render this archway impervious to moisture, great care was taken to 

 fill all the joints well with mortar, then a coating of cement mortar was 

 smoothly and evenly laid over the entire outside of the arch and walls. 

 When this had become hard, two coats of asphalt were applied; next 

 to this on the vertical walls, a layer of clay puddle one foot in thickness 

 was placed. This extended upon the inclined backing of the arch and 

 was reduced in thickness to a thin edge at the top. Outside of the 



