Handling dates

I have a problem with some functions handling dates, in packages 'date' and 
'survival' (they seem to be identical). For instance, from the documentation,

--------------------
mdy.date {survival}	

R Documentation

Convert to Julian Dates

Description

Given a month, day, and year, returns the number of days since January 1, 1960.
Usage

mdy.date(month, day, year, nineteen = TRUE, fillday = FALSE,
         fillmonth = FALSE)
----------------------------
but

library(survival)
mdy.date(12, 1, 1977)

[1] 1Dec77

Similar strange results appear in other date-related functions. I plan to 
write functions that converts, eg, "1977-01-31" to the real number 1977.084
and back. What function in  R  does what 'mdy.date' claims to do?

I'm on
  
platform i686-pc-linux-gnu
arch     i686
os       linux-gnu
system   i686, linux-gnu
status
major    2
minor    1.1
year     2005
month    06
day      20
language R

G??ran Brostr??m                    tel: +46 90 786 5223
Department of Statistics          fax: +46 90 786 6614
Ume?? University                   http://www.stat.umu.se/~goran.brostrom/
SE-90187 Ume??, Sweden             e-mail: gb at stat.umu.se