diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 9c7fdf3..6ce1fab 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -1963,73 +1963,6 @@ function system_regional_settings_submit($form, &$form_state) {
 }
 
 /**
- * Form builder; Configure the site date and time settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function system_date_time_settings() {
-  // Display any user-defined date formats.
-  $date_formats = system_get_date_formats();
-
-  $header = array(
-    'machine_name' => array('data' => t('Machine name')),
-    'name' => array('data' => t('Name')),
-    'pattern' => array('data' => t('Date format')),
-    'example' => array('data' => t('Example of use')),
-  );
-
-  $rows = array();
-  foreach ($date_formats as $date_format_id => $format_info) {
-    $rows[] = array(
-      $date_format_id,
-      $format_info['name'],
-      $pattern,
-      format_date(REQUEST_TIME, $date_format_id),
-    );
-  }
-
-  $variables = array(
-    'header' => $header,
-    'rows' => $rows,
-  );
-
-  return theme('table', $variables);
-}
-
-/**
- * Returns HTML for the date settings form.
- *
- * @param $variables
- *   An associative array containing:
- *   - form: A render element representing the form.
- *
- * @ingroup themeable
- */
-function theme_system_date_time_settings($variables) {
-  $form = $variables['form'];
-  $header = array(
-    t('Date type'),
-    t('Format'),
-    t('Operations'),
-  );
-
-  foreach (element_children($form['format']) as $key) {
-    $row = array();
-    $row[] = $form['format'][$key]['#title'];
-    $form['format'][$key]['#title_display'] = 'invisible';
-    $row[] = array('data' => drupal_render($form['format'][$key]));
-    $row[] = drupal_render($form['operations'][$key]);
-    $rows[] = $row;
-  }
-
-  $output = theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => array('id' => 'system-date-types')));
-  $output .= drupal_render_children($form);
-
-  return $output;
-}
-
-/**
  * Form builder; Configure the site's maintenance status.
  *
  * @ingroup forms
@@ -2583,7 +2516,7 @@ function system_date_delete_format_form_submit($form, &$form_state) {
  */
 function system_date_time_formats() {
   $header = array(
-    array('data' => t('Machine Name'), 'field' => 'machine_name'),
+    array('data' => t('Machine name'), 'field' => 'machine_name'),
     array('data' => t('Name'), 'field' => 'name'),
     array('data' => t('Pattern'), 'field' => 'pattern'),
     array('data' => t('Operations'))
@@ -2643,25 +2576,6 @@ function system_configure_date_formats_form($form, &$form_state, $date_format_id
   $format_info = config('system.date')->get('formats.' . $date_format_id);
   $patterns = $format_info['pattern'];
   $pattern = class_exists('IntlDateFormatter') ? $patterns[DrupalDateTime::INTL] : $patterns[DrupalDateTime::PHP];
-  if (empty($date_format_id)) {
-    $form['date_format_id'] = array(
-      '#type' => 'machine_name',
-      '#title' => t('Machine-readable name'),
-      '#description' => t('A unique machine-readable name. Can only contain lowercase letters, numbers, and underscores.'),
-      '#machine_name' => array(
-        'exists' => 'system_date_format_exists',
-        'source' => array('machine_name'),
-      ),
-    );
-    $now = '';
-  }
-  else {
-    $form['date_format_id'] = array(
-      '#type' => 'value',
-      '#value' => $date_format_id,
-    );
-    $now = t('Displayed as %date', array('%date' => format_date(REQUEST_TIME, $date_format_id)));
-  }
 
   $form['date_format_name'] = array(
     '#type' => 'textfield',
@@ -2671,6 +2585,20 @@ function system_configure_date_formats_form($form, &$form_state, $date_format_id
     '#default_value' => empty($format_info['name']) ? '' : $format_info['name']
   );
 
+  $now = !empty($date_format_id) ? t('Displayed as %date', array('%date' => format_date(REQUEST_TIME, $date_format_id))) : '';
+
+  $form['date_format_id'] = array(
+    '#type' => 'machine_name',
+    '#title' => t('Machine-readable name'),
+    '#description' => t('A unique machine-readable name. Can only contain lowercase letters, numbers, and underscores.'),
+    '#disabled' => !empty($date_format_id),
+    '#default_value' => $date_format_id,
+    '#machine_name' => array(
+      'exists' => 'system_date_format_exists',
+      'source' => array('date_format_name'),
+    ),
+  );
+
   if (class_exists('intlDateFormatter')) {
     $description = t('A user-defined date format. See the <a href="@url">PHP manual</a> for available options.', array('@url' => 'http://userguide.icu-project.org/formatparse/datetime'));
   }
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index c41172e..d561cee 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -1838,10 +1838,6 @@ function hook_theme($existing, $type, $theme, $path) {
       'render element' => 'requirements',
       'file' => 'system.admin.inc',
     ),
-    'system_date_time_settings' => array(
-      'render element' => 'form',
-      'file' => 'system.admin.inc',
-    ),
   );
 }
 
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index ce5e289..d4f9eb7 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -188,10 +188,6 @@ function system_theme() {
     'system_compact_link' => array(
       'variables' => array(),
     ),
-    'system_date_time_settings' => array(
-      'render element' => 'form',
-      'file' => 'system.admin.inc',
-    ),
     'system_date_format_localize_form' => array(
       'render element' => 'form',
     ),