R extract raster function not working

Question

I am having trouble with the extract function in the raster package. The raster is not empty, but when I perform the extract function all the values come back as NAs. I can plot the points over the raster fine and they show up in the same location.

library(dismo)
library(raster)

#Import CSV File
file <- paste("C:/Michelle/Michelle/R/CuskPA_Sept12_2013_1.csv", sep=" ")

#read file
cusk <- read.table(file, header=TRUE, sep=',')
cusks<- subset(cusks, SlongDD!=0 & SlatDD!=0)
cuskll <-cusks[,24:25]

#import raster
salvar <- raster("C:/Michelle/Michelle/R/Variables/salvar")
ext <-extent(-67.6, -64.9, 41.0, 44.7453)
salvarc <-crop(salvar, ext)

#extract from raster   
psalvar <- extract(salvarc, cuskll)

This is what I get when I'm finished the extraction

head(psalvar)
[1] NA NA NA NA NA NA

summary(psalvar)
Mode    NA's 
logical    3859 

The raster does not show up as empty.

> salvar
class       : RasterLayer 
dimensions  : 334, 240, 80160  (nrow, ncol, ncell)
resolution  : 0.01121539, 0.01121539  (x, y)
extent      : -67.59662, -64.90493, 41.00048, 44.74642  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs 
data source : in memory
names       : salvar 
values      : 0.01655413, 2.137321  (min, max)

Here is an example of the lat/longs in the file

head(cuskll)
SlatDD   SlongDD
1 44.41533 -66.07883
2 44.41167 -66.07733
3 44.44883 -66.07433
4 44.47067 -66.01217
5 44.47050 -66.01183
6 44.47633 -66.01450

Answer 1

Put longitude first and latitude second