This is just my own personal opinion, however I think you tried to show too much with this shot. I'm not trying to be rude here, but to me this shot gives one the impression of an image that might have been taken from a car window while driving down the road....could be any road side cemetery anywhere. It doesn't really give me any sense of "18th century" at all. I think I might have tried to isolate a couple of the more interesting headstones or maybe some other iconic feature to give the shot a better composition...perhaps something that distinctly identifies or associates this cemetery with the specific time period.
Also, I feel the colors are off here...perhaps just a bit over-processed. I like the blue in the sky, but the yellows seem too hot. From the data under your pic, it looks like you're shooting with Nikon...while I love the color depth you can get from Nikon DSLR's, it's been my experience that unless you really balance the color properly, they have a tendency to shift the yellows a tad...with my D90 for example, I'll usually bump the yellow saturation just a few degrees towards the reds, then desaturate them just a bit to give my images a more natural look. In either case, I'd definitely re-process the colors...maybe play around with the color balance in Adobe Camera RAW or something.