```r
g0<-ggplot(d,aes(x=d$Lshell))
g1<-g0+geom_histogram(color="grey",binwidth = 5)

g1+facet_wrap(~Site) +xlab("Text for x label") 
```

<img src="Quantitative_and_Spatial_files/figure-html/unnamed-chunk-187-1.png" width="672" />